/* ===== CSS DESIGN SYSTEM ===== */
:root {
    /* Colors */
    --bg-primary: #0a0a0f;
    --bg-secondary: #0f0f18;
    --bg-card: rgba(16, 16, 28, 0.7);
    --bg-card-hover: rgba(22, 22, 40, 0.85);
    --bg-input: rgba(12, 12, 22, 0.9);

    --text-primary: #eef0f6;
    --text-secondary: #9299b0;
    --text-muted: #5a6180;

    --accent-1: #6c5ce7;
    --accent-2: #a855f7;
    --accent-3: #818cf8;
    --accent-4: #38bdf8;

    --gradient-primary: linear-gradient(135deg, #6c5ce7 0%, #a855f7 50%, #818cf8 100%);
    --gradient-accent: linear-gradient(135deg, #a855f7 0%, #38bdf8 100%);
    --gradient-hero: linear-gradient(180deg, rgba(108,92,231,0.08) 0%, transparent 60%);

    --green: #22c55e;
    --green-glow: rgba(34,197,94,0.15);
    --red: #ef4444;
    --red-glow: rgba(239,68,68,0.15);
    --yellow: #eab308;
    --orange: #f97316;

    --border: rgba(120,120,180,0.1);
    --border-hover: rgba(120,120,180,0.25);
    --border-accent: rgba(108,92,231,0.4);

    --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 24px rgba(0,0,0,0.4);
    --shadow-lg: 0 8px 48px rgba(0,0,0,0.5);
    --shadow-glow: 0 0 30px rgba(108,92,231,0.15);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== RESET & BASE ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

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

::selection {
    background: rgba(108,92,231,0.4);
    color: #fff;
}

/* ===== ANIMATED BACKGROUND ===== */
.bg-grid {
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(rgba(108,92,231,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(108,92,231,0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    z-index: -2;
    pointer-events: none;
}

.bg-glow {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    z-index: -1;
    pointer-events: none;
    animation: glowFloat 20s ease-in-out infinite;
}
.bg-glow-1 {
    width: 600px; height: 600px;
    top: -200px; left: -200px;
    background: rgba(108,92,231,0.08);
}
.bg-glow-2 {
    width: 500px; height: 500px;
    top: 50%; right: -150px;
    background: rgba(168,85,247,0.06);
    animation-delay: -7s;
}
.bg-glow-3 {
    width: 400px; height: 400px;
    bottom: -100px; left: 30%;
    background: rgba(56,189,248,0.05);
    animation-delay: -14s;
}

@keyframes glowFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -20px) scale(1.05); }
    66% { transform: translate(-20px, 30px) scale(0.95); }
}

/* ===== NAVBAR ===== */
.navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 32px;
    background: rgba(10,10,15,0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    transition: var(--transition);
}
.navbar.scrolled {
    background: rgba(10,10,15,0.95);
    box-shadow: var(--shadow-sm);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.15rem;
}
.nav-icon {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 1.4rem;
    font-family: var(--font-mono);
    font-weight: 800;
}
.nav-title {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 4px;
}
.nav-link {
    padding: 6px 14px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}
.nav-link:hover {
    color: var(--text-primary);
    background: rgba(108,92,231,0.1);
}
.nav-link.active {
    color: var(--accent-2);
    background: rgba(168,85,247,0.12);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}
.mobile-menu-btn span {
    width: 22px;
    height: 2px;
    background: var(--text-secondary);
    border-radius: 2px;
    transition: var(--transition);
}
.mobile-menu-btn.open span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}
.mobile-menu-btn.open span:nth-child(2) { opacity: 0; }
.mobile-menu-btn.open span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 64px;
    left: 0; right: 0;
    background: rgba(10,10,15,0.98);
    backdrop-filter: blur(20px);
    padding: 16px;
    z-index: 999;
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    gap: 4px;
}
.mobile-menu.open {
    display: flex;
}
.mobile-link {
    padding: 12px 16px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}
.mobile-link:hover {
    color: var(--text-primary);
    background: rgba(108,92,231,0.1);
}

/* ===== LAYOUT ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 100px 0;
}
.section-alt {
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}
.section-tag {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--accent-2);
    margin-bottom: 16px;
}
.section-title {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 12px;
}
.section-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ===== HERO ===== */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 100px 32px 60px;
    gap: 60px;
    max-width: 1300px;
    margin: 0 auto;
    background: var(--gradient-hero);
}

.hero-content {
    flex: 1;
    min-width: 0;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 6px 16px;
    background: rgba(108,92,231,0.1);
    border: 1px solid rgba(108,92,231,0.2);
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-3);
    margin-bottom: 28px;
    animation: fadeInUp 0.6s ease;
}
.badge-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--green);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 24px;
    animation: fadeInUp 0.6s ease 0.1s both;
}

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

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    line-height: 1.8;
    max-width: 540px;
    margin-bottom: 36px;
    animation: fadeInUp 0.6s ease 0.2s both;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
    animation: fadeInUp 0.6s ease 0.3s both;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    font-size: 0.95rem;
    font-weight: 600;
    font-family: var(--font-sans);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    text-decoration: none;
    transition: var(--transition);
}
.btn-primary {
    background: var(--gradient-primary);
    color: #fff;
    box-shadow: 0 4px 20px rgba(108,92,231,0.3);
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 30px rgba(108,92,231,0.4);
}
.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-hover);
}
.btn-secondary:hover {
    border-color: var(--accent-2);
    background: rgba(168,85,247,0.08);
}

.hero-stats {
    display: flex;
    gap: 40px;
    animation: fadeInUp 0.6s ease 0.4s both;
}
.stat-item {
    display: flex;
    flex-direction: column;
}
.stat-number {
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.hero-visual {
    flex: 0 0 auto;
    width: 460px;
    animation: fadeInUp 0.8s ease 0.3s both;
}

.code-window {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}
.window-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    background: rgba(0,0,0,0.3);
    border-bottom: 1px solid var(--border);
}
.window-dots {
    display: flex;
    gap: 7px;
}
.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}
.dot-red { background: #ff5f57; }
.dot-yellow { background: #febc2e; }
.dot-green { background: #28c840; }
.window-title {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.window-code {
    padding: 20px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    line-height: 1.8;
    overflow-x: auto;
    color: var(--text-secondary);
}
.window-code .kw { color: #c792ea; }
.window-code .fn { color: #82aaff; }
.window-code .str { color: #c3e88d; }

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== INTRODUCTION SECTION ===== */
.intro-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.intro-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    transition: var(--transition);
}
.intro-card:hover {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
    transform: translateY(-2px);
}
.intro-card.full-width {
    grid-column: 1 / -1;
}
.card-icon {
    font-size: 2rem;
    margin-bottom: 16px;
}
.intro-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 12px;
}
.intro-card p {
    color: var(--text-secondary);
    margin-bottom: 12px;
}
.intro-card strong {
    color: var(--text-primary);
}

/* Pipeline */
.pipeline {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 20px;
    overflow-x: auto;
    padding-bottom: 4px;
}
.pipeline-step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 12px 18px;
    background: rgba(30,30,55,0.6);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    min-width: 90px;
    transition: var(--transition);
}
.pipeline-step.active {
    border-color: var(--accent-1);
    background: rgba(108,92,231,0.15);
    box-shadow: 0 0 20px rgba(108,92,231,0.15);
}
.pipe-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
}
.pipe-sub {
    font-size: 0.7rem;
    color: var(--text-muted);
}
.pipeline-arrow {
    color: var(--text-muted);
    font-size: 1.2rem;
    flex-shrink: 0;
}

/* Comparison Table */
.comparison-table-wrap {
    overflow-x: auto;
    margin-top: 16px;
}
.comparison-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}
.comparison-table th {
    padding: 12px 16px;
    text-align: left;
    font-weight: 600;
    color: var(--accent-3);
    border-bottom: 2px solid var(--border-accent);
    white-space: nowrap;
}
.comparison-table td {
    padding: 10px 16px;
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
}
.comparison-table td strong {
    color: var(--text-primary);
}
.comparison-table code {
    font-family: var(--font-mono);
    font-size: 0.85em;
    padding: 2px 6px;
    background: rgba(108,92,231,0.1);
    border-radius: 4px;
    color: var(--accent-3);
}
.comparison-table tr:hover td {
    background: rgba(108,92,231,0.04);
}

/* ===== GRAMMAR SECTION ===== */
.grammar-layout {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 24px;
}

.grammar-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
}
.grammar-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 12px;
}
.grammar-card h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 16px;
    margin-top: 20px;
    color: var(--accent-3);
}
.grammar-note {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.grammar-meta {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 12px 16px;
    background: rgba(0,0,0,0.2);
    border-radius: var(--radius-sm);
    margin-bottom: 8px;
}
.meta-item {
    font-size: 0.85rem;
    font-family: var(--font-mono);
    color: var(--text-secondary);
}
.meta-item strong {
    color: var(--accent-2);
}

.grammar-rules {
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.rule {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.88rem;
    transition: var(--transition);
}
.rule:hover {
    background: rgba(108,92,231,0.06);
}
.rule-num {
    color: var(--text-muted);
    font-size: 0.75rem;
    min-width: 24px;
}
.rule-lhs {
    color: var(--accent-2);
    font-weight: 600;
    min-width: 70px;
}
.rule-arrow {
    color: var(--text-muted);
}
.rule-rhs {
    color: var(--text-secondary);
}
.rule-rhs .terminal {
    color: var(--green);
    font-weight: 600;
}

.grammar-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}
.info-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
}
.info-card h4 {
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}
.info-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.precedence-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.prec-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 14px;
    background: rgba(0,0,0,0.2);
    border-left: 3px solid var(--accent-1);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.prec-item:nth-child(1) { border-color: #ef4444; }
.prec-item:nth-child(2) { border-color: #f97316; }
.prec-item:nth-child(3) { border-color: #eab308; }
.prec-item:nth-child(4) { border-color: #22c55e; }

.prec-level {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    min-width: 62px;
}
.prec-ops {
    font-size: 0.88rem;
    color: var(--text-secondary);
}
.prec-ops code {
    font-family: var(--font-mono);
    color: var(--accent-3);
    background: rgba(108,92,231,0.1);
    padding: 1px 5px;
    border-radius: 3px;
    font-size: 0.85em;
}

.props-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.props-list li {
    font-size: 0.9rem;
    color: var(--text-secondary);
    padding-left: 20px;
    position: relative;
}
.props-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--green);
    font-weight: 700;
}
.props-list li strong {
    color: var(--text-primary);
}

/* ===== PARSER SECTION ===== */
.parser-selector {
    display: flex;
    gap: 16px;
    margin-bottom: 40px;
    justify-content: center;
}
.parser-type-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 20px 32px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}
.parser-type-btn:hover {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
}
.parser-type-btn.active {
    border-color: var(--accent-1);
    background: rgba(108,92,231,0.12);
    box-shadow: 0 0 24px rgba(108,92,231,0.12);
}
.type-icon {
    font-size: 1.6rem;
}
.type-name {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
}
.type-desc {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Parser Input */
.parser-input-area {
    margin-bottom: 32px;
}
.input-wrapper {
    max-width: 700px;
    margin: 0 auto;
}
.input-label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
}
.input-row {
    display: flex;
    gap: 12px;
}
.expr-input {
    flex: 1;
    padding: 14px 18px;
    font-family: var(--font-mono);
    font-size: 1.05rem;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    outline: none;
    transition: var(--transition);
}
.expr-input:focus {
    border-color: var(--accent-1);
    box-shadow: 0 0 0 3px rgba(108,92,231,0.15);
}
.expr-input::placeholder {
    color: var(--text-muted);
}

.parse-btn {
    padding: 14px 28px;
    white-space: nowrap;
}

.quick-examples {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 14px;
    align-items: center;
}
.examples-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}
.example-btn {
    padding: 4px 12px;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 500;
    background: rgba(30,30,55,0.6);
    border: 1px solid var(--border);
    border-radius: 100px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}
.example-btn:hover {
    border-color: var(--accent-1);
    color: var(--text-primary);
    background: rgba(108,92,231,0.1);
}
.example-btn.error-example {
    border-color: rgba(239,68,68,0.3);
    color: rgba(239,68,68,0.8);
}
.example-btn.error-example:hover {
    border-color: var(--red);
    background: rgba(239,68,68,0.08);
}

/* ===== RESULTS ===== */
.results-area {
    max-width: 900px;
    margin: 0 auto 48px;
    animation: fadeInUp 0.4s ease;
}
.results-area.hidden {
    display: none;
}

.parse-status {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 20px;
    border-radius: var(--radius-md);
    margin-bottom: 16px;
    font-weight: 600;
    font-size: 0.95rem;
}
.parse-status.success {
    background: var(--green-glow);
    border: 1px solid rgba(34,197,94,0.3);
    color: var(--green);
}
.parse-status.error {
    background: var(--red-glow);
    border: 1px solid rgba(239,68,68,0.3);
    color: var(--red);
}

/* Result Tabs */
.result-tabs {
    display: flex;
    gap: 4px;
    margin-bottom: 2px;
}
.tab-btn {
    padding: 10px 20px;
    font-size: 0.88rem;
    font-weight: 600;
    font-family: var(--font-sans);
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    color: var(--text-muted);
    cursor: pointer;
    transition: var(--transition);
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}
.tab-btn:hover {
    color: var(--text-secondary);
    background: rgba(108,92,231,0.05);
}
.tab-btn.active {
    color: var(--accent-2);
    border-bottom-color: var(--accent-2);
    background: rgba(108,92,231,0.08);
}

.tab-contents {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 0 var(--radius-md) var(--radius-md) var(--radius-md);
    padding: 24px;
    min-height: 200px;
}
.tab-content {
    display: none;
}
.tab-content.active {
    display: block;
    animation: fadeInUp 0.3s ease;
}

/* Token List */
.token-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}
.token-chip {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 3px;
    padding: 8px 14px;
    background: rgba(30,30,55,0.6);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    animation: fadeInUp 0.3s ease var(--delay) both;
}
.token-type {
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
}
.token-value {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--accent-3);
}
.token-chip.token-number .token-value { color: #f9a825; }
.token-chip.token-operator .token-value { color: var(--accent-2); }
.token-chip.token-paren .token-value { color: var(--green); }
.token-chip.token-identifier .token-value { color: #38bdf8; }
.token-chip.token-eof .token-value { color: var(--text-muted); }

/* Step List */
.step-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
    max-height: 400px;
    overflow-y: auto;
}
.step-item {
    display: flex;
    gap: 12px;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    animation: fadeInUp 0.2s ease var(--delay) both;
    transition: var(--transition);
}
.step-item:hover {
    background: rgba(108,92,231,0.05);
}
.step-num {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
    min-width: 28px;
    padding-top: 2px;
}
.step-action {
    font-weight: 600;
    min-width: 90px;
    white-space: nowrap;
}
.step-action.action-enter { color: #22c55e; }
.step-action.action-match { color: #38bdf8; }
.step-action.action-exit { color: #eab308; }
.step-action.action-create { color: #a855f7; }
.step-action.action-error { color: #ef4444; }
.step-action.action-shift { color: #22c55e; }
.step-action.action-reduce { color: #f97316; }
.step-action.action-accept { color: #a855f7; }
.step-action.action-predict { color: #38bdf8; }
.step-desc {
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.82rem;
}

/* Tree Container */
.tree-container {
    position: relative;
    width: 100%;
    min-height: 350px;
    overflow: auto;
    border-radius: var(--radius-sm);
    background: rgba(0,0,0,0.2);
}
#tree-canvas {
    display: block;
}
.tree-controls {
    display: flex;
    gap: 6px;
    margin-bottom: 10px;
    justify-content: flex-end;
}
.tree-ctrl-btn {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(30,30,55,0.6);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: var(--transition);
}
.tree-ctrl-btn:hover {
    border-color: var(--accent-1);
    color: var(--text-primary);
}

/* AST JSON */
.ast-json {
    font-family: var(--font-mono);
    font-size: 0.82rem;
    line-height: 1.6;
    color: var(--text-secondary);
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 400px;
    overflow-y: auto;
}

/* Error Details */
.error-details {
    background: var(--red-glow);
    border: 1px solid rgba(239,68,68,0.3);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-top: 16px;
}
.error-details.hidden { display: none; }
.error-details h4 {
    color: var(--red);
    font-size: 1rem;
    margin-bottom: 12px;
}
.error-content {
    font-family: var(--font-mono);
    font-size: 0.88rem;
    color: var(--text-secondary);
}
.error-pointer {
    display: block;
    margin-top: 8px;
    padding: 10px 14px;
    background: rgba(0,0,0,0.3);
    border-radius: var(--radius-sm);
    white-space: pre;
    overflow-x: auto;
    line-height: 1.5;
}
.error-pointer .source-line {
    color: var(--text-primary);
}
.error-pointer .pointer-line {
    color: var(--red);
    font-weight: 700;
}
.error-msg {
    display: block;
    margin-top: 8px;
    color: var(--text-secondary);
}

/* ===== PARSER EXPLANATIONS ===== */
.parser-explanations {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-top: 48px;
}
.explanation-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    transition: var(--transition);
}
.explanation-card:hover {
    border-color: var(--border-hover);
}
.explanation-card h4 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 12px;
}
.explanation-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
}
.explain-pros-cons {
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.explain-pros-cons h5 {
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}
.explain-pros-cons ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.explain-pros-cons li {
    font-size: 0.82rem;
    color: var(--text-secondary);
    padding-left: 12px;
    position: relative;
}
.explain-pros-cons li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--text-muted);
}

/* ===== TESTING SECTION ===== */
.test-controls {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 32px;
}
.test-summary {
    font-size: 0.9rem;
    font-weight: 600;
}
.test-passed { color: var(--green); }
.test-failed { color: var(--red); }
.test-sep { color: var(--text-muted); margin: 0 4px; }

.test-results {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 16px;
}

.test-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 20px;
    transition: var(--transition);
    animation: fadeInUp 0.3s ease var(--delay) both;
}
.test-card:hover {
    border-color: var(--border-hover);
}
.test-card.test-pass {
    border-left: 3px solid var(--green);
}
.test-card.test-fail {
    border-left: 3px solid var(--red);
}
.test-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 10px;
}
.test-label {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}
.test-label.valid { color: var(--green); }
.test-label.invalid { color: var(--red); }
.test-status-icon {
    font-size: 1.1rem;
}
.test-input {
    font-family: var(--font-mono);
    font-size: 0.92rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}
.test-expected {
    font-size: 0.8rem;
    color: var(--text-muted);
}
.test-result-msg {
    font-size: 0.82rem;
    margin-top: 8px;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
}
.test-result-msg.pass {
    background: var(--green-glow);
    color: var(--green);
}
.test-result-msg.fail {
    background: var(--red-glow);
    color: var(--red);
}

/* ===== APPLICATIONS ===== */
.apps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}
.app-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}
.app-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition);
}
.app-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-3px);
}
.app-card:hover::before {
    opacity: 1;
}
.app-icon-wrap {
    margin-bottom: 16px;
}
.app-icon {
    font-size: 2.2rem;
}
.app-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 10px;
}
.app-card p {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}
.app-examples {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}
.app-tag {
    padding: 3px 10px;
    font-size: 0.72rem;
    font-weight: 600;
    background: rgba(108,92,231,0.1);
    border: 1px solid rgba(108,92,231,0.2);
    border-radius: 100px;
    color: var(--accent-3);
}

/* ===== CONCLUSION ===== */
.conclusion-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
}
.conclusion-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
}
.conclusion-card h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 16px;
}
.conclusion-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
    line-height: 1.7;
}
.conclusion-card ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.conclusion-card li {
    font-size: 0.9rem;
    color: var(--text-secondary);
    padding-left: 20px;
    position: relative;
    line-height: 1.6;
}
.conclusion-card li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent-2);
}
.conclusion-card li strong {
    color: var(--text-primary);
}

/* ===== FOOTER ===== */
.footer {
    padding: 40px 0;
    border-top: 1px solid var(--border);
}
.footer-content {
    text-align: center;
}
.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.1rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}
.footer-text {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 16px;
}
.footer-tech {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
}
.tech-tag {
    padding: 4px 12px;
    font-size: 0.72rem;
    font-weight: 600;
    background: rgba(30,30,55,0.6);
    border: 1px solid var(--border);
    border-radius: 100px;
    color: var(--text-muted);
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: rgba(108,92,231,0.3);
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
    background: rgba(108,92,231,0.5);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
    .hero-section {
        flex-direction: column;
        text-align: center;
        padding-top: 120px;
    }
    .hero-subtitle { margin: 0 auto 36px; }
    .hero-actions { justify-content: center; }
    .hero-stats { justify-content: center; }
    .hero-visual { width: 100%; max-width: 500px; }
    .parser-explanations { grid-template-columns: 1fr; }
    .grammar-layout { grid-template-columns: 1fr; }
    .apps-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-menu-btn { display: flex; }
    
    .section { padding: 64px 0; }
    .intro-grid { grid-template-columns: 1fr; }
    .apps-grid { grid-template-columns: 1fr; }
    .parser-selector { flex-direction: column; align-items: stretch; }
    .parser-type-btn { flex-direction: row; gap: 12px; }
    .input-row { flex-direction: column; }
    .hero-actions { flex-direction: column; align-items: center; }
    .comparison-table { font-size: 0.8rem; }
    .test-results { grid-template-columns: 1fr; }
    .pipeline { flex-wrap: wrap; justify-content: center; }
}