/* ==========================================================================
   EasyDB - Premium Dark Mode Theme (Vibrant Green & Royal Blue Points)
   Concept: State-of-the-Art Dark Aesthetic, Glassmorphism, Sleek Cyber Glow
   ========================================================================== */

:root {
    /* Color Palette - Vibrant Emerald & Electric Blue */
    --primary-green: #10b981;
    --primary-green-bright: #34d399;
    --primary-green-dark: #047857;
    
    --primary-blue: #3b82f6;
    --primary-blue-bright: #38bdf8;
    --primary-blue-dark: #1d4ed8;
    
    /* Dual Gradients */
    --gradient-green-blue: linear-gradient(135deg, #10b981 0%, #3b82f6 100%);
    --gradient-blue-green: linear-gradient(135deg, #3b82f6 0%, #34d399 100%);
    --gradient-hero: radial-gradient(circle at 50% 0%, #1e293b 0%, #090d16 80%);
    --gradient-card: linear-gradient(145deg, rgba(30, 41, 59, 0.8) 0%, rgba(15, 23, 42, 0.9) 100%);
    
    /* Dark Tints & Borders */
    --bg-main: #070a12;
    --bg-card: #0f172a;
    --card-border: #1e293b;
    --card-border-glow: rgba(59, 130, 246, 0.25);
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-light: #64748b;
    
    /* Accent & Functional */
    --danger-color: #f87171;
    --danger-bg: rgba(239, 68, 68, 0.15);
    --warning-color: #fbbf24;
    --success-color: #34d399;
    
    /* Shadow & Border Radius */
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4), 0 0 15px rgba(59, 130, 246, 0.12);
    --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.6), 0 0 25px rgba(16, 185, 129, 0.18);
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset & Base Styling */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    line-height: 1.7;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Typography & Helpers */
h1, h2, h3, h4 {
    color: var(--text-main);
    line-height: 1.3;
    font-weight: 700;
}

strong {
    color: var(--primary-blue-bright);
}

.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.text-success { color: var(--primary-green-bright); }
.text-danger { color: var(--danger-color); }
.text-emerald { color: var(--primary-green-bright); }
.text-blue { color: var(--primary-blue-bright); }

/* Gradient Highlight Text */
.highlight {
    background: var(--gradient-green-blue);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
    position: relative;
    display: inline-block;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(30, 41, 59, 0.8);
    color: var(--primary-blue-bright);
    padding: 6px 18px;
    border-radius: 20px;
    font-size: 0.88rem;
    font-weight: 700;
    border: 1px solid rgba(59, 130, 246, 0.3);
    box-shadow: 0 0 12px rgba(59, 130, 246, 0.15);
}

/* Navbar */
.navbar {
    position: sticky;
    top: 0;
    background: rgba(11, 15, 25, 0.88);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    z-index: 100;
    height: 72px;
    display: flex;
    align-items: center;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    font-size: 1.35rem;
    font-weight: 800;
    color: var(--text-main);
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: var(--gradient-green-blue);
    color: white;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.15rem;
    box-shadow: 0 0 16px rgba(16, 185, 129, 0.4);
}

.logo strong {
    background: var(--gradient-green-blue);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 28px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}

.nav-links a:hover {
    color: var(--primary-green-bright);
    text-shadow: 0 0 10px rgba(52, 211, 153, 0.5);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.4rem;
    color: var(--text-main);
    cursor: pointer;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 13px 28px;
    border-radius: var(--radius-md);
    font-weight: 700;
    font-size: 1rem;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--gradient-green-blue);
    color: white;
    box-shadow: 0 6px 20px rgba(16, 185, 129, 0.35);
}

.btn-primary:hover {
    background: var(--gradient-blue-green);
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(59, 130, 246, 0.45);
}

.btn-outline {
    background-color: rgba(30, 41, 59, 0.6);
    color: var(--text-main);
    border: 1px solid var(--card-border-glow);
}

.btn-outline:hover {
    background-color: #1e293b;
    border-color: var(--primary-green-bright);
    color: var(--primary-green-bright);
    transform: translateY(-2px);
}

/* Hero Section */
.hero {
    padding: 80px 0 60px 0;
    background: var(--gradient-hero);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.hero-container {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 40px;
    align-items: center;
}

.hero-content h1 {
    font-size: 2.8rem;
    margin: 18px 0 22px 0;
    letter-spacing: -0.02em;
}

.hero-content p {
    font-size: 1.15rem;
    color: var(--text-muted);
    margin-bottom: 32px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* Hero Visual Card Stack */
.hero-visual {
    display: flex;
    justify-content: center;
}

.db-illustration-card {
    width: 100%;
    max-width: 360px;
    background: var(--gradient-card);
    border-radius: var(--radius-lg);
    padding: 30px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--card-border-glow);
}

.db-stack {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.db-layer {
    padding: 18px 20px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: 14px;
    font-weight: 700;
    transition: var(--transition);
}

.layer-1 {
    background: rgba(16, 185, 129, 0.1);
    border: 1.5px solid rgba(16, 185, 129, 0.3);
    color: var(--primary-green-bright);
}
.layer-1 i { color: var(--primary-green-bright); font-size: 1.4rem; }

.layer-2 {
    background: rgba(59, 130, 246, 0.1);
    border: 1.5px solid rgba(59, 130, 246, 0.3);
    color: var(--primary-blue-bright);
}
.layer-2 i { color: var(--primary-blue-bright); font-size: 1.4rem; }

.layer-3 {
    background: rgba(56, 189, 248, 0.1);
    border: 1.5px solid rgba(56, 189, 248, 0.3);
    color: #e0f2fe;
}
.layer-3 i { color: #38bdf8; font-size: 1.4rem; }

.db-layer:hover {
    transform: translateX(8px);
    background: rgba(30, 41, 59, 0.9);
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.25);
}

/* Main Content Styling */
.main-content {
    padding-bottom: 60px;
}

.section-block {
    padding: 70px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.section-header {
    margin-bottom: 48px;
}

.section-tag {
    font-size: 0.85rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    background: var(--gradient-green-blue);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-transform: uppercase;
}

.section-header h2 {
    font-size: 2.1rem;
    margin: 8px 0 14px 0;
}

.section-header p {
    font-size: 1.1rem;
    color: var(--text-muted);
}

/* Card General */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 32px;
    border: 1px solid var(--card-border);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.card:hover {
    border-color: var(--card-border-glow);
    box-shadow: var(--shadow-md);
}

/* Grids */
.grid {
    display: grid;
    gap: 24px;
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.mb-8 { margin-bottom: 32px; }
.mb-4 { margin-bottom: 16px; }

/* Analogy Cards */
.card-analogy {
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.card-badge {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 0.78rem;
    font-weight: 800;
    padding: 4px 12px;
    border-radius: 12px;
}

.bg-blue-tag { background: rgba(59, 130, 246, 0.15); color: var(--primary-blue-bright); border: 1px solid rgba(59, 130, 246, 0.3); }
.bg-green-tag { background: rgba(16, 185, 129, 0.15); color: var(--primary-green-bright); border: 1px solid rgba(16, 185, 129, 0.3); }

.card-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
}

.icon-blue {
    background-color: rgba(59, 130, 246, 0.12);
    color: var(--primary-blue-bright);
    border: 1px solid rgba(59, 130, 246, 0.25);
}

.icon-emerald {
    background-color: rgba(16, 185, 129, 0.12);
    color: var(--primary-green-bright);
    border: 1px solid rgba(16, 185, 129, 0.25);
}

.card-analogy h3 {
    font-size: 1.35rem;
}

.card-analogy p {
    color: var(--text-muted);
    font-size: 0.98rem;
}

/* Comparison Box (Excel vs DB) */
.comparison-box {
    background: var(--bg-card);
}

.comparison-title {
    font-size: 1.45rem;
    text-align: center;
    margin-bottom: 6px;
}

.comparison-sub {
    text-align: center;
    margin-bottom: 30px;
    font-size: 0.95rem;
}

.comparison-grid {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 20px;
    align-items: center;
}

.comp-col {
    padding: 26px;
    border-radius: var(--radius-md);
}

.comp-excel {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--card-border);
}

.comp-db {
    background: linear-gradient(145deg, rgba(16, 185, 129, 0.08) 0%, rgba(59, 130, 246, 0.08) 100%);
    border: 1.5px solid var(--card-border-glow);
}

.comp-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 18px;
}

.comp-header i {
    font-size: 1.6rem;
}

.comp-excel i { color: #10b981; }
.comp-db i { color: var(--primary-blue-bright); }

.comp-header h4 {
    font-size: 1.2rem;
}

.comp-col ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.comp-col li {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 0.95rem;
    color: var(--text-muted);
}

.comp-vs {
    font-weight: 800;
    font-size: 1.1rem;
    color: var(--primary-blue-bright);
    background: #0f172a;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--card-border-glow);
}

/* DB Types Cards */
.db-type-card {
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.border-top-emerald {
    border-top: 5px solid var(--primary-green);
}

.border-top-blue {
    border-top: 5px solid var(--primary-blue);
}

.pill {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.bg-emerald-light { background-color: rgba(16, 185, 129, 0.15); color: var(--primary-green-bright); }
.bg-blue-light { background-color: rgba(59, 130, 246, 0.15); color: var(--primary-blue-bright); }

.type-header h3 {
    font-size: 1.4rem;
}

.type-subtitle {
    font-size: 0.88rem;
    color: var(--text-light);
}

.type-desc {
    color: var(--text-muted);
    font-size: 0.98rem;
}

.type-feature {
    background-color: rgba(15, 23, 42, 0.7);
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.92rem;
    border: 1px solid var(--card-border);
}

.tag-group {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 6px;
}

.tech-tag {
    background-color: #1e293b;
    color: #e2e8f0;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 6px;
    border: 1px solid var(--card-border);
}

.type-fit {
    padding: 14px 18px;
    border-radius: var(--radius-md);
    font-size: 0.92rem;
    border: 1px dashed var(--card-border);
    background: rgba(15, 23, 42, 0.5);
}

.bg-gray-50 { background-color: rgba(15, 23, 42, 0.5); }

/* Styled Table */
.table-responsive {
    overflow-x: auto;
}

.styled-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.95rem;
}

.styled-table th, .styled-table td {
    padding: 16px 20px;
    text-align: left;
    border-bottom: 1px solid var(--card-border);
}

.styled-table th {
    background: rgba(30, 41, 59, 0.8);
    color: var(--text-main);
    font-weight: 700;
}

.styled-table tr:last-child td {
    border-bottom: none;
}

.styled-table tbody tr:hover {
    background-color: rgba(30, 41, 59, 0.5);
}

/* CRUD Cards */
.crud-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 24px 20px;
    border: 1.5px solid var(--card-border);
    position: relative;
    text-align: center;
    transition: var(--transition);
}

.crud-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary-blue-bright);
    box-shadow: var(--shadow-md);
}

.crud-letter {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.crud-c .crud-letter { color: var(--primary-blue-bright); }
.crud-r .crud-letter { color: var(--primary-green-bright); }
.crud-u .crud-letter { color: var(--warning-color); }
.crud-d .crud-letter { color: var(--danger-color); }

.crud-card h4 {
    font-size: 1.1rem;
    margin-bottom: 4px;
}

.crud-sub {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 16px;
}

.crud-ex {
    background-color: #0f172a;
    padding: 10px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    border: 1px solid var(--card-border);
}

/* Interactive SQL Simulator */
.sql-simulator {
    background: #090d16;
    color: white;
    border: 1px solid var(--card-border-glow);
}

.sim-controls {
    display: flex;
    gap: 12px;
    margin: 24px 0;
    flex-wrap: wrap;
}

.sim-btn {
    background: #1e293b;
    color: #cbd5e1;
    border: 1px solid var(--card-border);
    padding: 10px 20px;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.sim-btn:hover {
    background: #334155;
    color: white;
}

.sim-btn.active {
    background: var(--gradient-green-blue);
    color: white;
    border-color: var(--primary-blue-bright);
    box-shadow: 0 0 18px rgba(59, 130, 246, 0.4);
}

.sim-display {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.code-box, .result-box {
    background: #141c2e;
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    padding: 20px;
}

.code-label, .result-label {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #64748b;
    margin-bottom: 12px;
    font-weight: 700;
}

pre {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
    color: #38bdf8;
    white-space: pre-wrap;
    word-break: break-all;
}

.result-content {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.result-badge {
    font-size: 0.9rem;
    font-weight: 600;
}

.table-mini {
    background: #090d16;
    padding: 12px 14px;
    border-radius: 8px;
    font-size: 0.88rem;
    color: #e2e8f0;
    border: 1px solid var(--card-border);
}

/* Quiz Section */
.quiz-card {
    max-width: 720px;
    margin: 0 auto;
    background: var(--bg-card);
}

.quiz-progress {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--primary-blue-bright);
    margin-bottom: 20px;
}

.quiz-question {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 20px;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 24px;
}

.quiz-opt-btn {
    background: #0f172a;
    border: 1.5px solid var(--card-border);
    padding: 16px 20px;
    border-radius: var(--radius-md);
    text-align: left;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-main);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.quiz-opt-btn:hover {
    background: #1e293b;
    border-color: var(--card-border-glow);
}

.quiz-opt-btn.correct {
    background: rgba(16, 185, 129, 0.2);
    border-color: var(--primary-green-bright);
    color: var(--primary-green-bright);
    font-weight: 700;
}

.quiz-opt-btn.wrong {
    background: var(--danger-bg);
    border-color: var(--danger-color);
    color: var(--danger-color);
}

.quiz-feedback {
    padding: 16px;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    margin-bottom: 20px;
    line-height: 1.6;
}

.quiz-feedback.correct {
    background: rgba(16, 185, 129, 0.15);
    border: 1px solid rgba(16, 185, 129, 0.3);
    color: var(--primary-green-bright);
}

.quiz-feedback.wrong {
    background: var(--danger-bg);
    border: 1px solid var(--danger-color);
    color: var(--danger-color);
}

/* Summary Banner */
.summary-banner {
    background: var(--gradient-green-blue);
    color: white;
    padding: 48px;
    border-radius: var(--radius-xl);
    text-align: center;
    margin-top: 60px;
    box-shadow: var(--shadow-lg);
}

.summary-content h2 {
    color: white;
    font-size: 1.8rem;
    margin-bottom: 12px;
}

.summary-content p {
    font-size: 1.1rem;
    opacity: 0.95;
}

/* Footer */
.footer {
    background: #05080e;
    color: #64748b;
    padding: 40px 0;
    font-size: 0.9rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2rem;
    font-weight: 700;
    color: white;
    margin-bottom: 6px;
}

.footer-logo strong {
    background: var(--gradient-green-blue);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Responsive Styles */
@media (max-width: 900px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-buttons {
        justify-content: center;
    }

    .comparison-grid {
        grid-template-columns: 1fr;
    }

    .comp-vs {
        margin: 0 auto;
    }

    .sim-display {
        grid-template-columns: 1fr;
    }

    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .nav-links {
        display: none;
    }
    
    .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: #0f172a;
        padding: 20px;
        border-bottom: 1px solid var(--card-border);
        box-shadow: var(--shadow-md);
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .card {
        padding: 20px;
    }
}