/* ============================================
   COA.4gl Tutorial — Premium Dark Theme CSS
   ============================================ */

:root {
    --bg-primary: #0f0f14;
    --bg-secondary: #16161e;
    --bg-card: #1a1a24;
    --bg-card-hover: #20202c;
    --bg-code: #12121a;
    --border-color: rgba(255,255,255,0.06);
    --border-hover: rgba(255,255,255,0.12);
    --text-primary: #e8e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent-primary: #818cf8;
    --accent-secondary: #a78bfa;
    --accent-gradient: linear-gradient(135deg, #6366f1, #a855f7);
    --font-main: 'Inter', 'Noto Sans Thai', -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 24px rgba(0,0,0,0.3);
    --shadow-lg: 0 8px 40px rgba(0,0,0,0.4);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* { box-sizing: border-box; }

body {
    font-family: var(--font-main);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* ============================================
   Navbar
   ============================================ */
.navbar-glass {
    background: rgba(15, 15, 20, 0.85);
    backdrop-filter: blur(20px) saturate(150%);
    -webkit-backdrop-filter: blur(20px) saturate(150%);
    border-bottom: 1px solid var(--border-color);
    padding: 0.6rem 0;
    transition: var(--transition);
}

.brand-icon {
    width: 36px;
    height: 36px;
    background: var(--accent-gradient);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: white;
}

.brand-title {
    font-weight: 700;
    font-size: 1rem;
    display: block;
    line-height: 1.2;
    color: var(--text-primary);
}

.brand-subtitle {
    font-size: 0.65rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1.5px;
    font-weight: 500;
}

.navbar-brand:hover { text-decoration: none; }

.nav-link {
    color: var(--text-secondary) !important;
    font-weight: 500;
    font-size: 0.88rem;
    padding: 0.5rem 0.9rem !important;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.nav-link:hover, .nav-link.active {
    color: var(--text-primary) !important;
    background: rgba(255,255,255,0.05);
}

.dropdown-menu-dark {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.5rem;
    box-shadow: var(--shadow-lg);
}

.dropdown-item {
    border-radius: var(--radius-sm);
    padding: 0.5rem 0.8rem;
    font-size: 0.85rem;
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
    padding-top: 64px;
    min-height: 100vh;
}

.section-padding {
    padding: 4rem 0;
}

.bg-section-alt {
    background: var(--bg-secondary);
}

/* ============================================
   Hero Section
   ============================================ */
.hero-section {
    position: relative;
    padding: 6rem 0 4rem;
    overflow: hidden;
}

.hero-bg-pattern {
    position: absolute;
    inset: 0;
    background: 
        radial-gradient(ellipse 80% 60% at 50% -20%, rgba(99, 102, 241, 0.12), transparent),
        radial-gradient(ellipse 60% 60% at 80% 50%, rgba(168, 85, 247, 0.08), transparent);
    pointer-events: none;
}

.min-vh-75 { min-height: 75vh; }

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 1rem;
    background: rgba(99, 102, 241, 0.15);
    border: 1px solid rgba(99, 102, 241, 0.25);
    border-radius: 100px;
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--accent-primary);
    letter-spacing: 0.5px;
}

.hero-title {
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 800;
    line-height: 1.15;
    margin-bottom: 1.2rem;
    letter-spacing: -0.02em;
}

.text-gradient {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 520px;
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

/* Hero Stats */
.stat-item {
    text-align: center;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 500;
}

/* Hero Code Preview */
.hero-code-preview {
    animation: floatUp 6s ease-in-out infinite alternate;
}

@keyframes floatUp {
    0% { transform: translateY(0); }
    100% { transform: translateY(-12px); }
}

.code-window {
    background: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.code-header {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 0.7rem 1rem;
    background: rgba(255,255,255,0.03);
    border-bottom: 1px solid var(--border-color);
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot-red { background: #ef4444; }
.dot-yellow { background: #eab308; }
.dot-green { background: #22c55e; }

.code-filename {
    margin-left: 0.6rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.code-body {
    padding: 1rem 1.2rem;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    line-height: 1.8;
    margin: 0;
    color: var(--text-secondary);
    overflow: hidden;
}

.code-comment { color: #546e7a; font-style: italic; }
.code-keyword { color: #c792ea; }
.code-type { color: #82aaff; }
.code-func { color: #f78c6c; }
.code-string { color: #c3e88d; }

/* ============================================
   Section Headers
   ============================================ */
.section-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.35rem 0.9rem;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.01em;
}

.section-desc {
    font-size: 1rem;
    color: var(--text-secondary);
    max-width: 500px;
    margin: 0 auto;
}

/* ============================================
   Lesson Cards (Home Page)
   ============================================ */
.lesson-card {
    display: block;
    text-decoration: none;
    color: inherit;
    height: 100%;
}

.lesson-card:hover { text-decoration: none; color: inherit; }

.lesson-card-inner {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.8rem;
    height: 100%;
    position: relative;
    overflow: hidden;
    transition: var(--transition);
}

.lesson-card-inner::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--card-accent);
    opacity: 0;
    transition: var(--transition);
}

.lesson-card:hover .lesson-card-inner {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0,0,0,0.3);
}

.lesson-card:hover .lesson-card-inner::before {
    opacity: 1;
}

.lesson-number {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-muted);
    letter-spacing: 2px;
    margin-bottom: 1rem;
}

.lesson-icon {
    width: 44px;
    height: 44px;
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--card-accent);
    margin-bottom: 1rem;
}

.lesson-card .lesson-title {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
    line-height: 1.4;
}

.lesson-subtitle {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.lesson-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.78rem;
    color: var(--text-muted);
}

.lesson-arrow {
    transition: var(--transition);
}

.lesson-card:hover .lesson-arrow {
    transform: translateX(4px);
    color: var(--accent-primary);
}

/* ============================================
   Flow Timeline
   ============================================ */
.flow-timeline {
    max-width: 640px;
    margin: 0 auto;
}

.flow-step {
    display: flex;
    gap: 1.2rem;
    align-items: flex-start;
    padding: 1.2rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.flow-step:hover {
    border-color: var(--step-color);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.08);
}

.flow-step-icon {
    width: 44px;
    height: 44px;
    min-width: 44px;
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--step-color);
}

.flow-step-content h5 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.2rem;
    font-family: var(--font-mono);
    color: var(--step-color);
}

.flow-step-content p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

.flow-connector {
    width: 2px;
    height: 24px;
    background: linear-gradient(to bottom, var(--border-color), rgba(99,102,241,0.3), var(--border-color));
    margin: 0 auto;
}

/* ============================================
   Info Cards (Home Page)
   ============================================ */
.info-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.8rem;
    height: 100%;
    transition: var(--transition);
}

.info-card:hover {
    transform: translateY(-3px);
    border-color: var(--border-hover);
}

.info-card-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    color: white;
    margin-bottom: 1rem;
}

.info-card h4 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 0.6rem;
}

.info-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 0;
    line-height: 1.7;
}

/* ============================================
   Lesson Page — Hero
   ============================================ */
.lesson-hero {
    padding: 6rem 0 2.5rem;
    position: relative;
    overflow: hidden;
    background: 
        radial-gradient(ellipse 70% 50% at 30% 0%, rgba(99, 102, 241, 0.1), transparent),
        var(--bg-primary);
}

.breadcrumb-custom {
    background: none;
    padding: 0;
    margin-bottom: 0.8rem;
}

.breadcrumb-custom .breadcrumb-item a {
    color: var(--text-muted);
    text-decoration: none;
}

.breadcrumb-custom .breadcrumb-item.active {
    color: var(--text-secondary);
}

.breadcrumb-custom .breadcrumb-item + .breadcrumb-item::before {
    color: var(--text-muted);
}

.lesson-hero-badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--accent-primary);
    letter-spacing: 1.5px;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}

.lesson-hero-title {
    font-size: clamp(1.6rem, 4vw, 2.4rem);
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -0.01em;
}

.lesson-hero-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
}

/* Progress Ring */
.lesson-progress-ring {
    position: relative;
    width: 110px;
    height: 110px;
    display: inline-block;
}

.lesson-progress-ring svg {
    transform: rotate(-90deg);
    width: 100%;
    height: 100%;
}

.ring-bg {
    fill: none;
    stroke: rgba(255,255,255,0.06);
    stroke-width: 8;
}

.ring-progress {
    fill: none;
    stroke: url(#progressGradient);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 339.29;
    stroke-dashoffset: calc(339.29 - (339.29 * var(--progress) / 100));
    transition: stroke-dashoffset 1s ease;
    stroke: var(--accent-primary);
}

.ring-text {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.ring-value {
    font-size: 1.6rem;
    font-weight: 800;
    line-height: 1;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.ring-label {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ============================================
   Lesson Sidebar
   ============================================ */
.lesson-sidebar {
    position: sticky;
    top: 80px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.2rem;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
}

.sidebar-title {
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1.2px;
    margin-bottom: 0.6rem;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.sidebar-link {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.45rem 0.6rem;
    border-radius: var(--radius-sm);
    font-size: 0.82rem;
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.sidebar-link:hover {
    background: rgba(255,255,255,0.04);
    color: var(--text-primary);
    text-decoration: none;
}

.sidebar-link.active {
    background: rgba(99, 102, 241, 0.1);
    color: var(--accent-primary);
}

.sidebar-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--text-muted);
    flex-shrink: 0;
    transition: var(--transition);
}

.sidebar-link.active .sidebar-dot {
    background: var(--accent-primary);
    box-shadow: 0 0 8px var(--accent-primary);
}

.sidebar-link-sm {
    font-size: 0.78rem;
    padding: 0.35rem 0.5rem;
}

.sidebar-number {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--text-muted);
    min-width: 20px;
}

/* ============================================
   Section Cards (Lesson Content)
   ============================================ */
.content-section {
    margin-bottom: 2.5rem;
}

.section-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
}

.section-card:hover {
    border-color: var(--border-hover);
}

.section-card-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.3rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.section-step-badge {
    width: 32px;
    height: 32px;
    min-width: 32px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
    color: white;
}

.section-heading {
    font-size: 1.15rem;
    font-weight: 600;
    margin: 0;
}

.section-content {
    padding: 1.3rem 1.5rem;
}

.section-content p {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.section-content code {
    background: rgba(99, 102, 241, 0.12);
    color: var(--accent-primary);
    padding: 0.15rem 0.45rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.83em;
}

.section-content ul, .section-content ol {
    padding-left: 1.2rem;
}

.section-content li {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.4rem;
    line-height: 1.7;
}

/* Info Box */
.info-box {
    background: rgba(99, 102, 241, 0.06);
    border: 1px solid rgba(99, 102, 241, 0.12);
    border-radius: var(--radius-md);
    padding: 1rem 1.2rem;
}

.info-box h6 {
    color: var(--accent-primary);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.info-box p, .info-box ul {
    font-size: 0.85rem;
    margin-bottom: 0;
}

.hint-text {
    font-size: 0.84rem;
    color: var(--text-muted);
}

/* Table in content */
.section-content .table {
    font-size: 0.84rem;
}

.section-content .table th {
    font-weight: 600;
    color: var(--text-secondary);
    border-color: var(--border-color);
}

.section-content .table td {
    color: var(--text-secondary);
    border-color: var(--border-color);
}

/* ============================================
   Code Block
   ============================================ */
.code-block {
    border-top: 1px solid var(--border-color);
    background: var(--bg-code);
}

.code-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 1.2rem;
    border-bottom: 1px solid rgba(255,255,255,0.04);
}

.code-block-label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
}

.copy-btn {
    font-size: 0.72rem;
    padding: 0.2rem 0.6rem;
}

.code-content {
    padding: 1rem 1.5rem;
    margin: 0;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.8;
    color: #c9d1d9;
    overflow-x: auto;
    tab-size: 4;
}

.code-content::-webkit-scrollbar {
    height: 5px;
}

.code-content::-webkit-scrollbar-track {
    background: transparent;
}

.code-content::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
}

/* ============================================
   Explanation Block
   ============================================ */
.explanation-block {
    border-top: 1px solid var(--border-color);
}

.explanation-header {
    padding: 0.7rem 1.5rem;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--accent-secondary);
    border-bottom: 1px solid rgba(255,255,255,0.03);
    background: rgba(167, 139, 250, 0.04);
}

.explanation-content {
    padding: 1rem 1.5rem;
}

.explanation-content p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.explanation-content code {
    background: rgba(99, 102, 241, 0.12);
    color: var(--accent-primary);
    padding: 0.15rem 0.45rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.83em;
}

.explanation-content ul, .explanation-content ol {
    padding-left: 1.2rem;
}

.explanation-content li {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 0.3rem;
}

/* ============================================
   Lesson Navigation
   ============================================ */
.lesson-nav {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
}

/* ============================================
   Summary Page
   ============================================ */
.summary-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    height: 100%;
}

.summary-card-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.summary-card-title i {
    color: var(--accent-primary);
}

.chart-container {
    height: 280px;
    position: relative;
}

/* Structure List */
.structure-list {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.structure-item {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.structure-bar {
    width: 100%;
    max-width: 50%;
    height: 8px;
    background: rgba(255,255,255,0.04);
    border-radius: 100px;
    overflow: hidden;
}

.structure-bar-fill {
    height: 100%;
    border-radius: 100px;
    transition: width 1s ease;
}

.structure-info {
    flex: 1;
    min-width: 0;
}

.structure-name {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    font-family: var(--font-mono);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.structure-lines {
    font-size: 0.7rem;
}

.structure-pct {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--accent-primary);
    min-width: 32px;
    text-align: right;
}

/* Module Badges */
.badge.bg-module-quality {
    background: rgba(99, 102, 241, 0.2) !important;
    color: #818cf8;
}

.badge.bg-module-common {
    background: rgba(34, 197, 94, 0.2) !important;
    color: #4ade80;
}

.badge.bg-module-item {
    background: rgba(234, 179, 8, 0.2) !important;
    color: #facc15;
}

.badge.bg-module-sales {
    background: rgba(239, 68, 68, 0.2) !important;
    color: #f87171;
}

/* Keyword Cards */
.keyword-card {
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.9rem 1rem;
    height: 100%;
    transition: var(--transition);
}

.keyword-card:hover {
    border-color: var(--border-hover);
    background: rgba(255,255,255,0.04);
}

.keyword-code {
    display: block;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-primary);
    background: rgba(99,102,241,0.1);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    margin-bottom: 0.4rem;
    word-break: break-word;
}

.keyword-desc {
    font-size: 0.82rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* Summary Lesson Links */
.summary-lesson-link {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.7rem 0.9rem;
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.82rem;
    transition: var(--transition);
    height: 100%;
}

.summary-lesson-link:hover {
    border-color: var(--link-color);
    background: rgba(255,255,255,0.04);
    color: var(--text-primary);
    text-decoration: none;
}

.sll-number {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--link-color);
    font-weight: 600;
    flex-shrink: 0;
}

.sll-title {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sll-arrow {
    color: var(--text-muted);
    transition: var(--transition);
}

.summary-lesson-link:hover .sll-arrow {
    transform: translateX(3px);
    color: var(--link-color);
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
    padding: 1.5rem 0;
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.site-footer p {
    font-size: 0.8rem;
}

/* ============================================
   Buttons
   ============================================ */
.btn-primary {
    background: var(--accent-gradient) !important;
    border: none !important;
    font-weight: 500;
    transition: var(--transition);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.btn-outline-light {
    border-color: rgba(255,255,255,0.15) !important;
    color: var(--text-secondary) !important;
    font-weight: 500;
}

.btn-outline-light:hover {
    background: rgba(255,255,255,0.06) !important;
    color: var(--text-primary) !important;
    border-color: rgba(255,255,255,0.25) !important;
}

/* ============================================
   Scrollbar Global
   ============================================ */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.08);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255,255,255,0.15);
}

/* ============================================
   Logic Programming Page
   ============================================ */
.logic-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 2rem;
    transition: var(--transition);
}

.logic-card:hover {
    border-color: var(--border-hover);
}

.logic-card-header {
    padding: 1.2rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.logic-card-header h2 {
    font-size: 1.1rem;
    font-weight: 700;
    margin: 0;
}

.logic-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.25rem 0.7rem;
    border-radius: 100px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    flex-shrink: 0;
}

.logic-badge-warn { background: rgba(245,158,11,0.15); color: #f59e0b; }
.logic-badge-info { background: rgba(99,102,241,0.15); color: #818cf8; }
.logic-badge-danger { background: rgba(239,68,68,0.15); color: #f87171; }

.logic-body { padding: 1.5rem; }

.logic-code-panel {
    border-radius: var(--radius-md);
    overflow: hidden;
    height: 100%;
}

.logic-code-before {
    background: rgba(239,68,68,0.04);
    border: 1px solid rgba(239,68,68,0.15);
}

.logic-code-after {
    background: rgba(34,197,94,0.04);
    border: 1px solid rgba(34,197,94,0.15);
}

.logic-code-label {
    padding: 0.5rem 0.8rem;
    font-size: 0.72rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.logic-code-before .logic-code-label { color: #f87171; }
.logic-code-after .logic-code-label { color: #4ade80; }

.logic-pre {
    padding: 0.8rem;
    margin: 0;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    line-height: 1.7;
    color: #c9d1d9;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.logic-explain {
    margin-top: 1.2rem;
    padding: 1rem 1.2rem;
    background: rgba(99,102,241,0.04);
    border: 1px solid rgba(99,102,241,0.1);
    border-radius: var(--radius-md);
}

.logic-explain h5 {
    font-size: 0.88rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--accent-primary);
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.logic-explain p { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 0.6rem; line-height: 1.7; }

.logic-tips { display: flex; flex-direction: column; gap: 0.4rem; margin-top: 0.5rem; }

.logic-tip {
    padding: 0.5rem 0.7rem;
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    display: flex;
    gap: 0.4rem;
    align-items: flex-start;
    line-height: 1.5;
}

.tip-good { background: rgba(34,197,94,0.06); border: 1px solid rgba(34,197,94,0.12); color: #86efac; }
.tip-warn { background: rgba(245,158,11,0.06); border: 1px solid rgba(245,158,11,0.12); color: #fcd34d; }

.tip-good i { color: #4ade80; }
.tip-warn i { color: #f59e0b; }

/* Refactoring Diagram */
.logic-refactor-diagram {
    text-align: center;
    padding: 1rem 0;
}

.refactor-from, .refactor-to {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.6rem;
}

.refactor-box {
    background: rgba(99,102,241,0.08);
    border: 1px solid rgba(99,102,241,0.2);
    border-radius: var(--radius-md);
    padding: 0.7rem 1rem;
    text-align: center;
    min-width: 140px;
}

.refactor-box h6 {
    margin: 0;
    font-size: 0.78rem;
    font-family: var(--font-mono);
    color: var(--accent-primary);
}

.refactor-box span {
    font-size: 0.68rem;
    color: var(--text-muted);
}

.refactor-box-big {
    background: rgba(239,68,68,0.08);
    border-color: rgba(239,68,68,0.2);
    min-width: 300px;
}

.refactor-box-big h6 { color: #f87171; }

.refactor-arrow {
    padding: 0.8rem 0;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-primary);
}

.refactor-arrow i { font-size: 1.2rem; }

/* Score Rings */
.score-item { text-align: center; }

.score-ring {
    position: relative;
    width: 70px;
    height: 70px;
    margin: 0 auto 0.4rem;
}

.score-ring svg {
    transform: rotate(-90deg);
    width: 100%;
    height: 100%;
}

.score-ring .ring-bg {
    fill: none;
    stroke: rgba(255,255,255,0.06);
    stroke-width: 6;
}

.score-ring .ring-fill {
    fill: none;
    stroke: var(--score-color);
    stroke-width: 6;
    stroke-linecap: round;
    stroke-dasharray: 213.6;
    stroke-dashoffset: calc(213.6 - (213.6 * var(--score) / 100));
    transition: stroke-dashoffset 1.5s ease;
}

.score-val {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--score-color);
}

.score-label {
    font-size: 0.7rem;
    color: var(--text-muted);
}

/* ============================================
   SQL Query Conversion Page
   ============================================ */
.sql-intro { margin-top: 0; }

.sql-step-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.3rem;
    height: 100%;
    text-align: center;
    transition: var(--transition);
}

.sql-step-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-3px);
}

.sql-step-num {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: white;
    font-weight: 700;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 0.7rem;
}

.sql-step-card h5 { font-size: 0.95rem; font-weight: 600; margin-bottom: 0.3rem; }
.sql-step-card p { font-size: 0.82rem; color: var(--text-muted); margin: 0; }

.sql-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 2rem;
    transition: var(--transition);
}

.sql-card:hover { border-color: var(--border-hover); }

.sql-card-header {
    padding: 1.2rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.sql-card-header h2 {
    font-size: 1.1rem;
    font-weight: 700;
    margin: 0.3rem 0 0.2rem;
}

.sql-card-header p {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin: 0;
}

.sql-card-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.25rem 0.7rem;
    border-radius: 100px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.sql-badge-header { background: rgba(6,182,212,0.15); color: #22d3ee; }
.sql-badge-detail { background: rgba(139,92,246,0.15); color: #a78bfa; }
.sql-badge-view { background: rgba(34,197,94,0.15); color: #4ade80; }
.sql-badge-diagram { background: rgba(245,158,11,0.15); color: #fbbf24; }
.sql-badge-api { background: rgba(236,72,153,0.15); color: #f472b6; }

.sql-card-body { padding: 1.5rem; }

.sql-source-panel, .sql-result-panel {
    border-radius: var(--radius-md);
    overflow: hidden;
    height: 100%;
}

.sql-source-panel {
    background: rgba(239,68,68,0.03);
    border: 1px solid rgba(239,68,68,0.12);
}

.sql-result-panel {
    background: rgba(34,197,94,0.03);
    border: 1px solid rgba(34,197,94,0.12);
}

.sql-source-label, .sql-result-label {
    padding: 0.5rem 0.8rem;
    font-size: 0.72rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    border-bottom: 1px solid rgba(255,255,255,0.04);
}

.sql-source-label { color: #f87171; }
.sql-result-label { color: #4ade80; }

.sql-pre {
    padding: 0.8rem;
    margin: 0;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    line-height: 1.7;
    color: #c9d1d9;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.sql-kw { color: #c792ea; font-weight: 500; }
.sql-str { color: #c3e88d; }
.sql-cm { color: #546e7a; font-style: italic; }

.sql-arrow-divider {
    font-size: 1.5rem;
    color: var(--accent-primary);
    opacity: 0.6;
}

.sql-note {
    margin-top: 1rem;
    padding: 0.8rem 1rem;
    background: rgba(6,182,212,0.04);
    border: 1px solid rgba(6,182,212,0.12);
    border-radius: var(--radius-md);
    display: flex;
    gap: 0.6rem;
    align-items: flex-start;
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.sql-note-icon { color: #22d3ee; font-size: 1rem; flex-shrink: 0; margin-top: 0.1rem; }

/* ERD Diagram */
.erd-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 1rem;
}

.erd-table {
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition);
}

.erd-table:hover { border-color: var(--border-hover); }

.erd-main {
    border-color: rgba(99,102,241,0.3);
    background: rgba(99,102,241,0.04);
}

.erd-table-head {
    padding: 0.5rem 0.7rem;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--accent-primary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.erd-table-head span {
    font-size: 0.65rem;
    color: var(--text-muted);
    font-weight: 400;
    font-family: var(--font-primary);
}

.erd-cols {
    list-style: none;
    padding: 0.3rem 0;
    margin: 0;
}

.erd-cols li {
    padding: 0.15rem 0.7rem;
    font-family: var(--font-mono);
    font-size: 0.68rem;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
    gap: 0.5rem;
}

.erd-cols li span {
    font-size: 0.6rem;
    color: var(--text-muted);
    font-family: var(--font-primary);
    text-align: right;
}

.erd-pk { color: #fbbf24 !important; font-weight: 600; }
.erd-fk { color: #818cf8 !important; }

/* SQL Compare Table */
.sql-compare-table {
    font-size: 0.82rem;
}

.sql-compare-table thead th {
    background: rgba(255,255,255,0.03);
    border-color: var(--border-color);
    font-weight: 600;
    color: var(--text-secondary);
}

.sql-compare-table td {
    border-color: var(--border-color);
    color: var(--text-secondary);
    vertical-align: middle;
}

.sql-compare-table code {
    background: rgba(99,102,241,0.1);
    color: var(--accent-primary);
    padding: 0.1rem 0.35rem;
    border-radius: 3px;
    font-size: 0.78em;
}

/* ============================================
   Business Logic Migration Section
   ============================================ */
.bl-layer {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.2rem;
    text-align: center;
    height: 100%;
    transition: var(--transition);
}

.bl-layer:hover { border-color: var(--border-hover); transform: translateY(-2px); }

.bl-layer-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    margin: 0 auto 0.6rem;
}

.bl-layer-db { border-color: rgba(6,182,212,0.25); }
.bl-layer-db .bl-layer-icon { background: rgba(6,182,212,0.15); color: #22d3ee; }
.bl-layer-app { border-color: rgba(245,158,11,0.25); }
.bl-layer-app .bl-layer-icon { background: rgba(245,158,11,0.15); color: #fbbf24; }
.bl-layer-api { border-color: rgba(139,92,246,0.25); }
.bl-layer-api .bl-layer-icon { background: rgba(139,92,246,0.15); color: #a78bfa; }

.bl-layer h5 { font-size: 0.9rem; font-weight: 700; margin-bottom: 0.2rem; }
.bl-layer p { font-size: 0.78rem; color: var(--text-muted); margin-bottom: 0.5rem; }
.bl-layer ul { list-style: none; padding: 0; margin: 0; text-align: left; }
.bl-layer ul li {
    font-size: 0.75rem;
    color: var(--text-secondary);
    padding: 0.15rem 0;
    padding-left: 0.8rem;
    position: relative;
}
.bl-layer ul li::before {
    content: '›';
    position: absolute;
    left: 0;
    color: var(--text-muted);
}

.bl-section-title {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--text-primary);
}

.bl-section-title i { color: #fbbf24; }

.bl-item {
    background: rgba(255,255,255,0.015);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    margin-bottom: 1rem;
    transition: var(--transition);
}

.bl-item:hover { border-color: var(--border-hover); }

.bl-item-header {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    padding: 0.8rem 1rem;
    border-bottom: 1px solid var(--border-color);
}

.bl-num {
    width: 28px;
    height: 28px;
    min-width: 28px;
    border-radius: 50%;
    background: rgba(245,158,11,0.15);
    color: #fbbf24;
    font-weight: 700;
    font-size: 0.78rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.bl-item-info { min-width: 0; }
.bl-item-info h5 { font-size: 0.88rem; font-weight: 600; margin: 0; line-height: 1.3; }

.bl-tag {
    display: inline-flex;
    align-items: center;
    padding: 0.15rem 0.5rem;
    border-radius: 100px;
    font-size: 0.62rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
    margin-top: 0.2rem;
}

.bl-tag-must { background: rgba(239,68,68,0.15); color: #f87171; }
.bl-tag-partial { background: rgba(245,158,11,0.15); color: #fbbf24; }
.bl-tag-sql { background: rgba(34,197,94,0.15); color: #4ade80; }
.bl-tag-config { background: rgba(139,92,246,0.15); color: #a78bfa; }

.bl-item-body {
    padding: 1rem;
}

.bl-item-body p { font-size: 0.85rem; color: var(--text-secondary); line-height: 1.6; margin-bottom: 0.6rem; }

.bl-code-box {
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: rgba(239,68,68,0.03);
    border: 1px solid rgba(239,68,68,0.1);
    height: 100%;
}

.bl-code-api {
    background: rgba(34,197,94,0.03);
    border-color: rgba(34,197,94,0.1);
}

.bl-code-label {
    padding: 0.4rem 0.7rem;
    font-size: 0.68rem;
    font-weight: 600;
    color: #f87171;
    display: flex;
    align-items: center;
    gap: 0.3rem;
    border-bottom: 1px solid rgba(255,255,255,0.04);
}

.bl-callout {
    display: flex;
    gap: 0.5rem;
    align-items: flex-start;
    padding: 0.7rem 0.8rem;
    border-radius: var(--radius-sm);
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin-top: 0.6rem;
}

.bl-callout i { flex-shrink: 0; margin-top: 0.1rem; }

.bl-callout-warn {
    background: rgba(245,158,11,0.05);
    border: 1px solid rgba(245,158,11,0.12);
}
.bl-callout-warn i { color: #f59e0b; }

.bl-callout-info {
    background: rgba(6,182,212,0.05);
    border: 1px solid rgba(6,182,212,0.12);
}
.bl-callout-info i { color: #22d3ee; }

/* Flow Chain */
.bl-flow-chain {
    display: flex;
    align-items: stretch;
    gap: 0.4rem;
    margin: 0.6rem 0;
    flex-wrap: wrap;
}

.bl-flow-box {
    flex: 1;
    min-width: 120px;
    background: rgba(99,102,241,0.06);
    border: 1px solid rgba(99,102,241,0.15);
    border-radius: var(--radius-sm);
    padding: 0.6rem;
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
}

.bl-flow-step {
    width: 22px;
    height: 22px;
    min-width: 22px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: white;
    font-size: 0.65rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
}

.bl-flow-content { min-width: 0; }
.bl-flow-content strong { font-size: 0.78rem; font-family: var(--font-mono); color: var(--accent-primary); display: block; }
.bl-flow-content span { font-size: 0.68rem; color: var(--text-muted); }

.bl-flow-arrow {
    display: flex;
    align-items: center;
    gap: 0.2rem;
    font-size: 0.68rem;
    color: var(--text-muted);
    padding: 0 0.2rem;
    flex-shrink: 0;
    white-space: nowrap;
}

/* Check marks */
.bl-check { color: #4ade80; font-weight: 600; }
.bl-check-api { color: #fbbf24; font-weight: 600; }
.bl-check-danger { color: #f87171; font-weight: 600; }

/* ============================================
   Interactive ERD Diagram
   ============================================ */
.erd-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem 1.5rem;
    padding: 0.8rem 1rem;
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: 1.5rem;
    font-size: 0.72rem;
    color: var(--text-muted);
}

.erd-legend-item { display: flex; align-items: center; gap: 0.4rem; }
.erd-legend-dot { width: 10px; height: 10px; border-radius: 50%; flex-shrink: 0; }
.erd-legend-line { width: 24px; height: 3px; border-radius: 2px; flex-shrink: 0; }
.erd-legend-line-solid { background: #818cf8; }
.erd-legend-line-dash { background: repeating-linear-gradient(90deg, #4ade80 0, #4ade80 4px, transparent 4px, transparent 7px); }
.erd-legend-badge { width: 16px; height: 10px; border-radius: 3px; flex-shrink: 0; }
.erd-legend-badge-main { background: rgba(99,102,241,0.3); border: 1px solid rgba(99,102,241,0.5); }
.erd-legend-badge-ref { background: rgba(6,182,212,0.15); border: 1px solid rgba(6,182,212,0.3); }

.erd-canvas { position: relative; }
.erd-svg { position: absolute; inset: 0; pointer-events: none; z-index: 1; }

/* ERD Rows */
.erd-row {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    position: relative;
    z-index: 2;
}

/* ERD Table Cards */
.erd-tbl {
    flex: 1;
    min-width: 200px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition);
}

.erd-tbl:hover { border-color: var(--border-hover); transform: translateY(-2px); }

.erd-tbl-main { border-color: rgba(99,102,241,0.25); }
.erd-tbl-ref { border-color: rgba(6,182,212,0.15); }

.erd-tbl-head {
    padding: 0.6rem 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.erd-tbl-head i { font-size: 0.9rem; flex-shrink: 0; }
.erd-tbl-head > div { min-width: 0; flex: 1; }
.erd-tbl-head-main { background: rgba(99,102,241,0.06); }
.erd-tbl-head-main i { color: #818cf8; }
.erd-tbl-head-ref { background: rgba(6,182,212,0.04); }
.erd-tbl-head-ref i { color: #22d3ee; }

.erd-tbl-name {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--text-primary);
    display: block;
    line-height: 1.2;
}

.erd-tbl-desc {
    font-size: 0.62rem;
    color: var(--text-muted);
    display: block;
}

.erd-tbl-badge {
    flex-shrink: 0;
    font-size: 0.55rem;
    font-weight: 700;
    padding: 0.1rem 0.4rem;
    border-radius: 100px;
    letter-spacing: 0.5px;
}

.erd-badge-main { background: rgba(99,102,241,0.15); color: #818cf8; }
.erd-badge-ref { background: rgba(6,182,212,0.1); color: #22d3ee; }

.erd-tbl-body { padding: 0.2rem 0; }

/* ERD Columns */
.erd-col {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.2rem 0.6rem;
    font-size: 0.68rem;
    border-left: 2px solid transparent;
    transition: background 0.2s;
}

.erd-col:hover { background: rgba(255,255,255,0.02); }

.erd-col-pk { border-left-color: #fbbf24; background: rgba(251,191,36,0.03); }
.erd-col-fk { border-left-color: #818cf8; background: rgba(129,140,248,0.03); }

.erd-col-key {
    width: 20px;
    font-size: 0.55rem;
    font-weight: 700;
    text-align: center;
    flex-shrink: 0;
}

.erd-col-pk .erd-col-key { color: #fbbf24; }
.erd-col-fk .erd-col-key { color: #818cf8; }

.erd-col-name {
    font-family: var(--font-mono);
    font-weight: 600;
    color: var(--text-primary);
    min-width: 60px;
    flex-shrink: 0;
}

.erd-col-desc {
    color: var(--text-muted);
    font-size: 0.62rem;
    margin-left: auto;
    text-align: right;
}

/* Horizontal Connector (between sccoa003 and sccoa004) */
.erd-connector-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.2rem;
    padding: 0 0.3rem;
    min-width: 50px;
    flex-shrink: 0;
}

.erd-conn-line {
    width: 3px;
    height: 30px;
    background: #818cf8;
    border-radius: 2px;
    display: none;
}

.erd-conn-text {
    font-size: 0.62rem;
    font-weight: 700;
    color: #818cf8;
    font-family: var(--font-mono);
    white-space: nowrap;
    background: rgba(99,102,241,0.1);
    padding: 0.15rem 0.4rem;
    border-radius: 100px;
}

.erd-conn-arrow { color: #818cf8; font-size: 0.9rem; }

/* Vertical Connectors */
.erd-vertical-connectors {
    display: flex;
    gap: 1rem;
    padding: 0 0;
    position: relative;
    z-index: 2;
}

.erd-v-conn {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0.3rem 0;
    min-width: 100px;
}

.erd-v-line {
    width: 2px;
    height: 24px;
    background: repeating-linear-gradient(180deg, #4ade80 0, #4ade80 3px, transparent 3px, transparent 6px);
    margin-bottom: 0.2rem;
}

.erd-v-line-solid {
    background: #818cf8 !important;
}

.erd-v-label {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    font-weight: 600;
    color: #22d3ee;
    background: rgba(6,182,212,0.08);
    padding: 0.1rem 0.4rem;
    border-radius: 100px;
    white-space: nowrap;
}

.erd-v-conn small {
    font-size: 0.55rem;
    color: var(--text-muted);
    margin-top: 0.1rem;
}

.erd-v-spacer { flex: 1; }

/* Relationship Explanation */
.erd-explain h5 {
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--text-primary);
}

.erd-explain h5 i { color: #fbbf24; }

.erd-rel-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 0.8rem;
}

.erd-rel-item {
    background: rgba(255,255,255,0.015);
    border-radius: var(--radius-sm);
    padding: 0.8rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.erd-rel-item:hover { border-color: var(--border-hover); }

.erd-rel-join { border-left: 3px solid #818cf8; }
.erd-rel-left { border-left: 3px solid #4ade80; }

.erd-rel-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.4rem;
}

.erd-rel-num {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: white;
    font-size: 0.65rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.erd-rel-header strong {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    display: block;
}

.erd-rel-type {
    font-size: 0.6rem;
    color: var(--text-muted);
}

.erd-rel-item p {
    font-size: 0.78rem;
    color: var(--text-secondary);
    margin: 0.3rem 0;
    line-height: 1.5;
}

.erd-rel-sql {
    margin-top: 0.3rem;
    padding: 0.3rem 0.5rem;
    background: rgba(99,102,241,0.04);
    border-radius: var(--radius-sm);
}

.erd-rel-sql code {
    font-size: 0.65rem;
    color: #c792ea;
    font-family: var(--font-mono);
}

/* Data Flow */
.erd-dataflow h5 {
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--text-primary);
}

.erd-dataflow h5 i { color: #22d3ee; }

.erd-flow-steps {
    display: flex;
    align-items: stretch;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.erd-flow-step-card {
    flex: 1;
    min-width: 150px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0.7rem;
    display: flex;
    gap: 0.5rem;
    align-items: flex-start;
    transition: var(--transition);
}

.erd-flow-step-card:hover { border-color: var(--border-hover); transform: translateY(-2px); }

.erd-fs-num {
    width: 24px;
    height: 24px;
    min-width: 24px;
    border-radius: 50%;
    background: var(--accent-gradient);
    color: white;
    font-size: 0.7rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
}

.erd-fs-content { min-width: 0; }
.erd-fs-content strong { font-size: 0.72rem; font-family: var(--font-mono); color: var(--accent-primary); display: block; }
.erd-fs-content span { font-size: 0.65rem; color: var(--text-muted); display: block; margin: 0.1rem 0; }
.erd-fs-content code { font-size: 0.6rem; color: #c792ea; }

.erd-fs-arrow {
    display: flex;
    align-items: center;
    color: var(--accent-primary);
    font-size: 0.8rem;
    flex-shrink: 0;
    opacity: 0.5;
}


/* ============================================
   Fullcode Page
   ============================================ */
.fullcode-section {
    padding-top: 2rem;
}

.fc-sidebar {
    position: sticky;
    top: 76px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1rem;
    max-height: calc(100vh - 96px);
    overflow-y: auto;
}

.fc-nav-link {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.35rem 0.5rem;
    font-size: 0.72rem;
    flex-wrap: nowrap;
}

.fc-nav-text {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    min-width: 0;
}

.fc-nav-lines {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    color: var(--text-muted);
    flex-shrink: 0;
    opacity: 0.7;
}

.fc-mobile-nav {
    position: sticky;
    top: 64px;
    z-index: 10;
    background: var(--bg-primary);
    padding: 0.5rem 0;
}

.fc-mobile-nav .form-select {
    background-color: var(--bg-card);
    border-color: var(--border-color);
    color: var(--text-primary);
    font-size: 0.85rem;
}

/* Code Block */
.fc-block {
    margin-bottom: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
    scroll-margin-top: 80px;
}

.fc-block:hover {
    border-color: var(--border-hover);
}

.fc-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.8rem;
    padding: 0.8rem 1rem;
    cursor: pointer;
    user-select: none;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.fc-block-header:hover {
    background: rgba(255,255,255,0.02);
}

.fc-block-title {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    min-width: 0;
}

.fc-block-icon {
    width: 30px;
    height: 30px;
    min-width: 30px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    color: white;
}

.fc-block-info {
    min-width: 0;
}

.fc-block-info h3 {
    font-size: 0.9rem;
    font-weight: 600;
    margin: 0;
    line-height: 1.3;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.fc-block-meta {
    font-size: 0.7rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.fc-toggle-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    padding: 0.3rem;
    cursor: pointer;
    transition: var(--transition);
    flex-shrink: 0;
}

.fc-chevron {
    transition: transform 0.3s ease;
    font-size: 0.85rem;
}

.fc-chevron-open {
    transform: rotate(180deg);
}

/* Annotation */
.fc-annotation {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.fc-annotation-open {
    max-height: 200px;
}

.fc-annotation-inner {
    padding: 0.7rem 1rem;
    font-size: 0.82rem;
    color: var(--text-secondary);
    background: rgba(99, 102, 241, 0.04);
    border-bottom: 1px solid var(--border-color);
    line-height: 1.6;
}

/* Code Table */
.fc-code-area {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.fc-code-table {
    width: 100%;
    border-collapse: collapse;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    line-height: 1.65;
}

.fc-line {
    transition: background 0.15s ease;
}

.fc-line:hover {
    background: rgba(255,255,255,0.03);
}

.fc-line-comment {
    opacity: 0.6;
}

.fc-line-num {
    padding: 0 0.6rem 0 0.8rem;
    text-align: right;
    color: var(--text-muted);
    user-select: none;
    white-space: nowrap;
    width: 1%;
    min-width: 40px;
    border-right: 2px solid var(--fc-color, var(--border-color));
    font-size: 0.68rem;
    opacity: 0.5;
    vertical-align: top;
}

.fc-line-code {
    padding: 0 0.8rem;
    white-space: pre;
}

.fc-line-code pre {
    margin: 0;
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
    color: #c9d1d9;
    white-space: pre;
}

/* Back to Top */
.fc-back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--accent-gradient);
    border: none;
    color: white;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 100;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.fc-btt-show {
    opacity: 1;
    transform: translateY(0);
}

.fc-back-to-top:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

/* ============================================
   Responsive — All Breakpoints
   ============================================ */

/* Extra large (1400px+) */
@media (min-width: 1400px) {
    .fc-code-table { font-size: 0.8rem; }
    .fc-block-info h3 { font-size: 1rem; }
}

/* Large screens (992px – 1199px) */
@media (max-width: 1199.98px) {
    .hero-section { padding: 5rem 0 3rem; }
    .fc-nav-lines { display: none; }
}

/* Medium screens / tablets (768px – 991px) */
@media (max-width: 991.98px) {
    .hero-section { padding: 4.5rem 0 2.5rem; }
    .min-vh-75 { min-height: auto; }
    .section-padding { padding: 2.5rem 0; }
    .lesson-hero { padding: 5rem 0 1.5rem; }
    .fullcode-section { padding-top: 1rem; }

    .hero-stats { gap: 2rem; }
    .stat-value { font-size: 1.5rem; }

    .section-title { font-size: 1.6rem; }
    .section-desc { font-size: 0.9rem; }
    
    .lesson-card-inner { padding: 1.3rem; }
    .lesson-card .lesson-title { font-size: 0.95rem; }

    .info-card { padding: 1.3rem; }

    /* Summary page */
    .chart-container { height: 240px; }
    .structure-bar { max-width: 40%; }
}

/* Small screens / phones (576px – 767px) */
@media (max-width: 767.98px) {
    .hero-title { font-size: 1.8rem; }
    .hero-desc { font-size: 0.95rem; }
    .hero-stats { gap: 1.5rem; }

    .section-padding { padding: 2rem 0; }
    .section-title { font-size: 1.4rem; }

    .flow-step { 
        flex-direction: row; 
        gap: 0.8rem;
        padding: 0.9rem;
    }
    .flow-step-icon {
        width: 36px;
        height: 36px;
        min-width: 36px;
        font-size: 1rem;
    }
    .flow-step-content h5 { font-size: 0.85rem; }
    .flow-step-content p { font-size: 0.8rem; }

    .structure-bar { max-width: 30%; }

    /* Lesson page */
    .lesson-hero { padding: 4.5rem 0 1.2rem; }
    .lesson-hero-title { font-size: 1.3rem; }
    .section-card-header { padding: 1rem; gap: 0.7rem; }
    .section-heading { font-size: 1rem; }
    .section-content { padding: 1rem; }
    .code-content { padding: 0.8rem 1rem; font-size: 0.73rem; }
    .explanation-content { padding: 0.8rem 1rem; }
    .lesson-nav { padding: 1rem; }
    .lesson-nav .btn { font-size: 0.85rem; padding: 0.5rem 0.8rem; }

    /* Summary */
    .chart-container { height: 220px; }
    .keyword-card { padding: 0.7rem 0.8rem; }
    .keyword-code { font-size: 0.72rem; }

    /* Fullcode */
    .fc-block-header { padding: 0.7rem 0.8rem; }
    .fc-block-icon { width: 26px; height: 26px; min-width: 26px; font-size: 0.75rem; }
    .fc-block-info h3 { font-size: 0.82rem; }
    .fc-annotation-inner { font-size: 0.78rem; padding: 0.6rem 0.8rem; }
    .fc-code-table { font-size: 0.68rem; }
    .fc-line-num { padding: 0 0.3rem 0 0.5rem; min-width: 32px; font-size: 0.6rem; }
    .fc-line-code { padding: 0 0.5rem; }

    .fc-back-to-top { 
        width: 38px; height: 38px; 
        bottom: 1.2rem; right: 1.2rem; 
        font-size: 0.95rem; 
    }

    /* Info cards */
    .info-card { padding: 1.2rem; }
    .info-card-icon { width: 40px; height: 40px; font-size: 1.1rem; }
    .info-card h4 { font-size: 0.95rem; }

    /* Logic page */
    .logic-card-header { padding: 0.8rem 1rem; gap: 0.6rem; }
    .logic-card-header h2 { font-size: 0.95rem; }
    .logic-body { padding: 1rem; }
    .logic-pre { font-size: 0.65rem; }
    .logic-explain { padding: 0.8rem; }
    .refactor-box { min-width: 100px; padding: 0.5rem 0.7rem; }
    .refactor-box-big { min-width: 200px; }
    .score-ring { width: 56px; height: 56px; }
    .score-val { font-size: 0.7rem; }
    .score-label { font-size: 0.62rem; }

    /* SQL page */
    .sql-card-header { padding: 0.8rem 1rem; }
    .sql-card-header h2 { font-size: 0.95rem; }
    .sql-card-body { padding: 1rem; }
    .sql-pre { font-size: 0.65rem; }
    .erd-row { flex-direction: column; }
    .erd-connector-label { flex-direction: row; padding: 0.3rem 0; }
    .erd-connector-label .erd-conn-arrow { transform: rotate(90deg); }
    .erd-vertical-connectors { flex-direction: column; gap: 0; }
    .erd-v-spacer { display: none; }
    .erd-rel-grid { grid-template-columns: 1fr; }
    .erd-flow-steps { flex-direction: column; }
    .erd-fs-arrow { transform: rotate(90deg); justify-content: center; }
    .erd-col-desc { font-size: 0.58rem; }

    /* Footer */
    .site-footer .row { text-align: center; }
    .site-footer .text-md-end { text-align: center !important; }
}

/* Extra small screens (< 576px) */
@media (max-width: 575.98px) {
    .navbar-glass { padding: 0.4rem 0; }
    .brand-title { font-size: 0.9rem; }
    .brand-subtitle { font-size: 0.55rem; letter-spacing: 1px; }
    .brand-icon { width: 30px; height: 30px; font-size: 0.9rem; }

    .hero-section { padding: 4rem 0 2rem; }
    .hero-title { font-size: 1.5rem; }
    .hero-desc { font-size: 0.88rem; }
    .hero-badge { font-size: 0.7rem; padding: 0.3rem 0.8rem; }
    .hero-stats { flex-wrap: wrap; gap: 1rem; }
    .stat-value { font-size: 1.3rem; }
    .stat-label { font-size: 0.65rem; }

    .hero-section .btn-lg { font-size: 0.88rem; padding: 0.6rem 1rem; }
    
    .section-title { font-size: 1.2rem; }
    .section-badge { font-size: 0.65rem; padding: 0.25rem 0.6rem; }

    .lesson-hero { padding: 4rem 0 1rem; }
    .lesson-hero-title { font-size: 1.15rem; }
    .lesson-hero-subtitle { font-size: 0.85rem; }
    .lesson-hero-badge { font-size: 0.65rem; }

    .section-card-header { 
        flex-direction: column; 
        align-items: flex-start; 
        gap: 0.5rem; 
        padding: 0.8rem;
    }
    .section-step-badge { width: 28px; height: 28px; min-width: 28px; font-size: 0.75rem; }
    .section-heading { font-size: 0.92rem; }
    .section-content { padding: 0.8rem; }
    .section-content p { font-size: 0.85rem; }
    .section-content li { font-size: 0.83rem; }
    .code-block-header { padding: 0.4rem 0.8rem; flex-wrap: wrap; gap: 0.3rem; }
    .code-content { padding: 0.6rem 0.8rem; font-size: 0.68rem; line-height: 1.7; }
    .explanation-content { padding: 0.7rem 0.8rem; }
    .explanation-content p { font-size: 0.83rem; }
    .explanation-content li { font-size: 0.8rem; }

    .lesson-nav { padding: 0.8rem; }
    .lesson-nav .d-flex { flex-direction: column; gap: 0.6rem; }
    .lesson-nav .btn { width: 100%; }

    /* Summary */
    .summary-card { padding: 1rem; }
    .summary-card-title { font-size: 0.9rem; }
    .chart-container { height: 200px; }
    .structure-item { flex-wrap: wrap; gap: 0.4rem; }
    .structure-bar { max-width: 100%; order: 3; width: 100%; }
    .structure-info { order: 1; }
    .structure-pct { order: 2; }
    .summary-lesson-link { font-size: 0.78rem; padding: 0.5rem 0.7rem; }

    /* Tables */
    .table { font-size: 0.75rem; }
    .table th, .table td { padding: 0.35rem 0.5rem; }

    /* Fullcode */
    .fc-block { margin-bottom: 1rem; border-radius: var(--radius-md); }
    .fc-block-header { padding: 0.6rem; gap: 0.5rem; }
    .fc-block-icon { width: 24px; height: 24px; min-width: 24px; font-size: 0.7rem; border-radius: 6px; }
    .fc-block-info h3 { font-size: 0.78rem; }
    .fc-block-meta { font-size: 0.6rem; }
    .fc-annotation-inner { font-size: 0.75rem; padding: 0.5rem 0.6rem; }
    .fc-code-table { font-size: 0.62rem; line-height: 1.55; }
    .fc-line-num { padding: 0 0.2rem 0 0.3rem; min-width: 28px; font-size: 0.55rem; }
    .fc-line-code { padding: 0 0.4rem; }

    .flow-step { padding: 0.7rem; gap: 0.6rem; }
    .flow-step-icon { width: 32px; height: 32px; min-width: 32px; font-size: 0.9rem; }
    .flow-step-content h5 { font-size: 0.8rem; }
    .flow-step-content p { font-size: 0.75rem; }
    .flow-connector { height: 16px; }

    .info-box { padding: 0.7rem 0.8rem; }
    .info-box h6 { font-size: 0.78rem; }
    .info-box p, .info-box ul { font-size: 0.78rem; }
    .info-box li { font-size: 0.78rem; }

    /* Logic page */
    .logic-card-header { padding: 0.6rem 0.8rem; flex-direction: column; align-items: flex-start; gap: 0.3rem; }
    .logic-card-header h2 { font-size: 0.85rem; }
    .logic-body { padding: 0.8rem; }
    .logic-pre { font-size: 0.6rem; line-height: 1.55; padding: 0.6rem; }
    .logic-explain { padding: 0.6rem 0.7rem; margin-top: 0.8rem; }
    .logic-explain h5 { font-size: 0.78rem; }
    .logic-explain p { font-size: 0.78rem; }
    .logic-tip { font-size: 0.72rem; padding: 0.4rem 0.5rem; }
    .refactor-box { min-width: 80px; padding: 0.4rem 0.6rem; }
    .refactor-box h6 { font-size: 0.68rem; }
    .refactor-box span { font-size: 0.58rem; }
    .refactor-box-big { min-width: 180px; }
    .score-ring { width: 50px; height: 50px; }
    .score-val { font-size: 0.62rem; }
    .score-label { font-size: 0.58rem; }

    /* SQL page */
    .sql-step-card { padding: 0.9rem; }
    .sql-step-card h5 { font-size: 0.82rem; }
    .sql-step-card p { font-size: 0.72rem; }
    .sql-step-num { width: 30px; height: 30px; font-size: 0.78rem; }
    .sql-card-header { padding: 0.7rem 0.8rem; }
    .sql-card-header h2 { font-size: 0.85rem; }
    .sql-card-header p { font-size: 0.75rem; }
    .sql-card-body { padding: 0.8rem; }
    .sql-pre { font-size: 0.6rem; line-height: 1.55; padding: 0.6rem; }
    .sql-note { font-size: 0.75rem; padding: 0.6rem 0.7rem; }
    .erd-grid { grid-template-columns: 1fr; }
    .erd-table-head { font-size: 0.7rem; }
    .erd-cols li { font-size: 0.6rem; }
    .sql-compare-table { font-size: 0.72rem; }
}