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

:root {
    --bg: #0a0a0f;
    --bg-alt: #111118;
    --surface: #1a1a24;
    --border: #2a2a3a;
    --text: #e8e8f0;
    --text-muted: #8888aa;
    --accent: #FF9900;
    --accent-blue: #146EB4;
    --accent-green: #2ECC71;
    --accent-purple: #9B59B6;
    --radius: 12px;
}

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 0.75rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(10, 10, 15, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.1rem;
}

.nav-links { display: flex; gap: 1.25rem; align-items: center; }
.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    transition: color 0.2s;
    padding: 0.25rem 0;
}
.nav-links a:hover, .nav-links a.active { color: var(--accent); }
.nav-tool-link {
    background: rgba(255,153,0,0.1) !important;
    border: 1px solid rgba(255,153,0,0.3);
    padding: 0.35rem 0.75rem !important;
    border-radius: 6px;
    color: var(--accent) !important;
}

/* Nav Dropdown */
.nav-dropdown { position: relative; }
.dropdown-trigger { cursor: pointer; }
.dropdown-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    margin-top: 0.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.5rem 0;
    min-width: 220px;
    max-height: 70vh;
    overflow-y: auto;
    z-index: 1001;
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
}
.nav-dropdown.open .dropdown-menu { display: block; }
.dropdown-menu a {
    display: block;
    padding: 0.5rem 1.25rem;
    font-size: 0.83rem;
    color: var(--text-muted);
    text-decoration: none;
    transition: background 0.15s, color 0.15s;
}
.dropdown-menu a:hover { background: rgba(255,153,0,0.08); color: var(--accent); }

/* Page System */
.page {
    display: none;
    min-height: 100vh;
    padding-top: 60px;
    animation: fadeIn 0.4s ease;
}
.page.active { display: block; }

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

.page-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 4rem 6rem;
}

/* Page Navigation */
.page-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 2rem;
    background: rgba(10, 10, 15, 0.95);
    backdrop-filter: blur(12px);
    border-top: 1px solid var(--border);
    z-index: 999;
}

.nav-btn {
    padding: 0.6rem 1.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}
.nav-btn:hover { border-color: var(--accent); color: var(--accent); }
.nav-btn:disabled { opacity: 0.3; cursor: not-allowed; }
.nav-btn.next { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 600; }
.nav-btn.next:hover { box-shadow: 0 4px 15px rgba(255,153,0,0.3); }
.nav-btn.next:disabled { background: var(--surface); color: var(--text-muted); border-color: var(--border); box-shadow: none; }

.page-dots { display: flex; gap: 0.5rem; }
.page-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--border);
    cursor: pointer;
    transition: all 0.2s;
}
.page-dot.active { background: var(--accent); transform: scale(1.3); }
.page-dot:hover { background: var(--text-muted); }

/* Hero */
.hero {
    min-height: calc(100vh - 60px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 2rem 4rem;
    gap: 4rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255,153,0,0.08) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content { max-width: 600px; }
.hero-content h1 { font-size: 3.5rem; font-weight: 800; line-height: 1.1; margin-bottom: 1.5rem; }
.gradient-text {
    background: linear-gradient(135deg, #FF9900, #FFC300, #FF9900);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero-subtitle { font-size: 1.25rem; color: var(--text-muted); margin-bottom: 2rem; max-width: 500px; }

.cta-btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    background: var(--accent);
    color: #000;
    text-decoration: none;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}
.cta-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(255,153,0,0.3); }

/* Hero Visual */
.hero-visual { position: relative; width: 400px; height: 350px; }
.floating-card {
    position: absolute;
    padding: 0.75rem 1.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    font-weight: 500;
    font-size: 0.95rem;
    animation: float 3s ease-in-out infinite;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}
.card-1 { top: 10%; left: 5%; animation-delay: 0s; }
.card-2 { top: 5%; left: 55%; animation-delay: 0.4s; border-color: var(--accent); }
.card-3 { top: 40%; left: 30%; animation-delay: 0.8s; border-color: var(--accent-green); }
.card-4 { top: 55%; left: 60%; animation-delay: 1.2s; border-color: var(--accent-blue); }
.card-5 { top: 75%; left: 15%; animation-delay: 1.6s; border-color: var(--accent-purple); }
@keyframes float { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

/* Section Headers */
.section-header { margin-bottom: 2.5rem; }
.section-number { display: inline-block; font-size: 0.8rem; font-weight: 700; color: var(--accent); letter-spacing: 2px; margin-bottom: 0.5rem; }
.section-header h2 { font-size: 2.5rem; font-weight: 700; margin-bottom: 0.75rem; }
.section-desc { font-size: 1.1rem; color: var(--text-muted); max-width: 650px; }

/* Concept Grid */
.concept-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 2rem; }
.concept-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    transition: border-color 0.3s, transform 0.2s;
}
.concept-card:hover { border-color: var(--accent); transform: translateY(-3px); }
.concept-card.wide { grid-column: span 2; }
.concept-icon { font-size: 2rem; margin-bottom: 1rem; }
.concept-card h3 { font-size: 1.3rem; margin-bottom: 0.5rem; }
.concept-card p { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 0.75rem; }

/* Frames Demo */
.frames-demo { display: flex; gap: 4px; margin-top: 0.5rem; }
.frame { width: 40px; height: 30px; border-radius: 4px; animation: frameFlash 1.5s infinite; }
.f1 { background: #FF9900; animation-delay: 0s; }
.f2 { background: #FFA633; animation-delay: 0.1s; }
.f3 { background: #FFB366; animation-delay: 0.2s; }
.f4 { background: #FFC080; animation-delay: 0.3s; }
.f5 { background: #FFCC99; animation-delay: 0.4s; }
@keyframes frameFlash { 0%, 100% { opacity: 0.4; } 50% { opacity: 1; } }

/* Resolution Bars */
.resolution-bars { display: flex; flex-direction: column; gap: 0.5rem; margin-top: 0.5rem; }
.res-bar { display: flex; align-items: center; gap: 0.75rem; }
.res-label { font-size: 0.8rem; width: 40px; color: var(--text-muted); font-weight: 500; }
.res-bar .bar { height: 8px; background: linear-gradient(90deg, var(--accent), var(--accent-blue)); border-radius: 4px; }
.res-detail { font-size: 0.7rem; color: var(--text-muted); margin-left: auto; }

/* Bitrate Visual */
.bitrate-visual { display: flex; flex-direction: column; gap: 0.75rem; margin-top: 0.5rem; }
.bitrate-pipe {
    display: flex; align-items: center; gap: 0.75rem;
    padding: 0.5rem 1rem;
    background: rgba(255,153,0,0.05); border-radius: 20px; border: 1px solid var(--border);
}
.bitrate-pipe span { font-size: 0.8rem; color: var(--accent); font-weight: 600; min-width: 55px; }
.bitrate-pipe.thin { height: 28px; }
.bitrate-pipe.medium { height: 36px; }
.bitrate-pipe.thick { height: 48px; }
.data-dots {
    flex: 1; height: 4px;
    background: repeating-linear-gradient(90deg, var(--accent) 0px, var(--accent) 4px, transparent 4px, transparent 8px);
    border-radius: 2px; animation: flowDots 1s linear infinite;
}
@keyframes flowDots { 0% { background-position: 0; } 100% { background-position: 16px; } }

/* Container Visual */
.container-visual { margin-top: 0.5rem; }
.container-box { border: 2px dashed var(--border); border-radius: 10px; padding: 1.25rem; }
.container-label { font-size: 0.8rem; color: var(--text-muted); margin-bottom: 0.75rem; font-weight: 600; }
.codec-inner { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.codec-item { padding: 0.5rem 1rem; border-radius: 6px; font-size: 0.8rem; font-weight: 600; }
.video-codec { background: rgba(255,153,0,0.15); color: var(--accent); border: 1px solid rgba(255,153,0,0.3); }
.audio-codec { background: rgba(20,110,180,0.15); color: var(--accent-blue); border: 1px solid rgba(20,110,180,0.3); }
.sub-codec { background: rgba(46,204,113,0.15); color: var(--accent-green); border: 1px solid rgba(46,204,113,0.3); }

/* Info Callout */
.info-callout {
    display: flex; align-items: flex-start; gap: 1rem; padding: 1.5rem;
    background: rgba(255,153,0,0.05); border: 1px solid rgba(255,153,0,0.2); border-radius: var(--radius);
    margin-top: 2rem;
}
.callout-icon { font-size: 1.5rem; }
.callout-text { font-size: 0.95rem; color: var(--text-muted); }
.callout-text strong { color: var(--text); }
.callout-text a { color: var(--accent); }

/* Frame Types Visual */
.frame-type-visual { display: flex; align-items: center; gap: 0.5rem; margin-top: 1rem; flex-wrap: wrap; }
.ft-item {
    display: flex; flex-direction: column; align-items: center; gap: 0.25rem;
    padding: 0.75rem 1rem; border-radius: 8px; min-width: 70px;
}
.ft-item span { font-weight: 700; font-size: 1.1rem; }
.ft-item small { font-size: 0.65rem; color: var(--text-muted); }
.i-frame { background: rgba(255,153,0,0.15); color: var(--accent); border: 1px solid rgba(255,153,0,0.3); }
.p-frame { background: rgba(20,110,180,0.15); color: var(--accent-blue); border: 1px solid rgba(20,110,180,0.3); }
.b-frame { background: rgba(155,89,182,0.15); color: var(--accent-purple); border: 1px solid rgba(155,89,182,0.3); }
.ft-arrow { color: var(--text-muted); font-size: 1rem; }

/* Codec Comparison */
.codec-comparison { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; margin-bottom: 2rem; }
.codec-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 2rem; position: relative; transition: transform 0.2s; }
.codec-card:hover { transform: translateY(-3px); }
.codec-card.featured { border-color: var(--accent); box-shadow: 0 0 30px rgba(255,153,0,0.1); }
.codec-badge { position: absolute; top: 1rem; right: 1rem; padding: 0.25rem 0.75rem; border-radius: 20px; font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; }
.codec-badge.old { background: rgba(136,136,170,0.2); color: var(--text-muted); }
.codec-badge.current { background: rgba(255,153,0,0.2); color: var(--accent); }
.codec-badge.future { background: rgba(46,204,113,0.2); color: var(--accent-green); }
.codec-card h3 { font-size: 1.3rem; margin-bottom: 0.5rem; }
.codec-card > p { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 1.5rem; }
.codec-stats { display: flex; flex-direction: column; gap: 0.75rem; }
.stat { display: flex; flex-direction: column; gap: 0.25rem; }
.stat-label { font-size: 0.75rem; color: var(--text-muted); font-weight: 500; }
.stat-bar { height: 6px; background: var(--border); border-radius: 3px; overflow: hidden; }
.stat-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent-blue)); border-radius: 3px; }

/* Rendition Ladder */
.rendition-ladder { display: flex; flex-direction: column; gap: 0.5rem; margin-top: 1rem; }
.rendition { display: flex; justify-content: space-between; align-items: center; padding: 0.6rem 1.25rem; border-radius: 8px; font-weight: 600; font-size: 0.9rem; transition: transform 0.2s; }
.rendition:hover { transform: translateX(5px); }
.rendition-detail { font-size: 0.8rem; font-weight: 400; opacity: 0.7; }
.r-4k { background: rgba(255,153,0,0.15); color: #FF9900; border-left: 3px solid #FF9900; }
.r-1080 { background: rgba(20,110,180,0.15); color: #4DA8DA; border-left: 3px solid #4DA8DA; }
.r-720 { background: rgba(46,204,113,0.15); color: #2ECC71; border-left: 3px solid #2ECC71; }
.r-480 { background: rgba(155,89,182,0.15); color: #9B59B6; border-left: 3px solid #9B59B6; }
.r-360 { background: rgba(136,136,170,0.1); color: var(--text-muted); border-left: 3px solid var(--text-muted); }

/* ABR Chart */
.abr-visual { margin-top: 1rem; }
.abr-chart { width: 100%; height: 120px; }
.abr-legend { display: flex; gap: 1.5rem; margin-top: 0.75rem; }
.legend-item { display: flex; align-items: center; gap: 0.5rem; font-size: 0.8rem; color: var(--text-muted); }
.dot { width: 10px; height: 10px; border-radius: 50%; }
.dot.orange { background: #FF9900; }
.dot.blue { background: #146EB4; }

/* Protocol Visual */
.protocol-visual { margin-top: 0.5rem; }
.playlist-file { display: inline-block; padding: 0.4rem 1rem; background: rgba(255,153,0,0.1); border: 1px solid rgba(255,153,0,0.3); border-radius: 6px; font-size: 0.8rem; font-weight: 600; color: var(--accent); margin-bottom: 0.75rem; }
.playlist-file.dash { background: rgba(20,110,180,0.1); border-color: rgba(20,110,180,0.3); color: var(--accent-blue); }
.segments { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.segment { padding: 0.35rem 0.75rem; background: var(--border); border-radius: 4px; font-size: 0.75rem; font-weight: 500; color: var(--text-muted); }
.dash-seg { background: rgba(20,110,180,0.1); }

/* Manifest Section Styles */
.manifest-explainer { display: flex; flex-direction: column; gap: 3rem; }
.manifest-section h3 { font-size: 1.4rem; margin-bottom: 0.75rem; }
.manifest-section > p { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 1rem; }

.code-block {
    background: #0d1117;
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 1.25rem;
}
.code-header {
    padding: 0.5rem 1rem;
    background: rgba(255,255,255,0.03);
    border-bottom: 1px solid var(--border);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    font-family: 'JetBrains Mono', monospace;
}
.code-block pre {
    padding: 1.25rem;
    overflow-x: auto;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    line-height: 1.7;
}
.code-block code { color: var(--text); }
.code-block .tag { color: #FF9900; }
.code-block .attr { color: #79c0ff; }
.code-block .val { color: #7ee787; }
.code-block .str { color: #a5d6ff; }
.code-block .url { color: #d2a8ff; }
.code-block .comment { color: #484f58; font-style: italic; }

.tag-explanation { display: flex; flex-direction: column; gap: 0.5rem; }
.tag-item {
    display: flex; align-items: baseline; gap: 0.75rem;
    padding: 0.5rem 0.75rem;
    background: var(--surface);
    border-radius: 6px;
    font-size: 0.85rem;
}
.tag-item code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--accent);
    background: rgba(255,153,0,0.1);
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    white-space: nowrap;
}
.tag-item span { color: var(--text-muted); }

.tag-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1rem;
}
.tag-card {
    padding: 1.25rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
}
.tag-card code {
    display: inline-block;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    color: var(--accent);
    background: rgba(255,153,0,0.1);
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    margin-bottom: 0.5rem;
}
.tag-card p { color: var(--text-muted); font-size: 0.85rem; margin: 0; }

/* Services Grid */
.services-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1.5rem; }
.service-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 2rem; transition: transform 0.2s, border-color 0.3s; }
.service-card:hover { transform: translateY(-3px); border-color: rgba(255,153,0,0.4); }
.service-icon { width: 48px; height: 48px; border-radius: 10px; display: flex; align-items: center; justify-content: center; margin-bottom: 1.25rem; }
.service-card h3 { font-size: 1.2rem; margin-bottom: 0.25rem; }
.service-tagline { font-size: 0.85rem; color: var(--accent); font-weight: 500; margin-bottom: 0.75rem; }
.service-card > p { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 1rem; }
.service-use-case { padding: 0.75rem 1rem; background: rgba(255,153,0,0.05); border-radius: 8px; font-size: 0.8rem; color: var(--text-muted); }
.service-use-case strong { color: var(--text); }

/* Workflow Blocks */
.workflow-block { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 2.5rem; margin-bottom: 2.5rem; }
.workflow-level { margin-bottom: 1.5rem; }
.workflow-level h3 { font-size: 1.4rem; margin-top: 0.5rem; margin-bottom: 0.5rem; }
.workflow-level p { color: var(--text-muted); font-size: 0.95rem; }
.level-badge { display: inline-block; padding: 0.25rem 0.75rem; border-radius: 20px; font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; }
.level-badge.beginner { background: rgba(46,204,113,0.15); color: var(--accent-green); }
.level-badge.intermediate { background: rgba(20,110,180,0.15); color: var(--accent-blue); }
.level-badge.advanced { background: rgba(255,153,0,0.15); color: var(--accent); }
.level-badge.expert { background: rgba(155,89,182,0.15); color: var(--accent-purple); }

.workflow-diagram { display: flex; align-items: center; gap: 0.5rem; padding: 2rem 1rem; overflow-x: auto; background: rgba(0,0,0,0.2); border-radius: 10px; margin-bottom: 1.5rem; }
.workflow-diagram.complex { flex-direction: column; align-items: stretch; }
.workflow-row { display: flex; align-items: center; gap: 0.5rem; justify-content: center; }
.workflow-arrow-down { text-align: center; font-size: 1.5rem; color: var(--text-muted); padding: 0.5rem; }
.workflow-step { display: flex; flex-direction: column; align-items: center; gap: 0.25rem; padding: 1rem 1.25rem; background: var(--surface); border: 1px solid var(--border); border-radius: 10px; min-width: 110px; text-align: center; transition: transform 0.2s; }
.workflow-step:hover { transform: scale(1.05); }
.workflow-step.highlight { border-color: var(--accent); box-shadow: 0 0 15px rgba(255,153,0,0.1); }
.workflow-step.highlight.purple { border-color: var(--accent-purple); box-shadow: 0 0 15px rgba(155,89,182,0.1); }
.workflow-step.highlight.green { border-color: var(--accent-green); box-shadow: 0 0 15px rgba(46,204,113,0.1); }
.workflow-step.highlight.orange { border-color: #F39C12; box-shadow: 0 0 15px rgba(243,156,18,0.1); }
.step-icon { font-size: 1.5rem; }
.step-label { font-size: 0.8rem; font-weight: 600; }
.step-desc { font-size: 0.7rem; color: var(--text-muted); }
.workflow-arrow { color: var(--text-muted); font-size: 1.25rem; flex-shrink: 0; }
.workflow-explanation { padding: 1rem 1.5rem; background: rgba(255,153,0,0.03); border-left: 3px solid var(--accent); border-radius: 0 8px 8px 0; }
.workflow-explanation p { font-size: 0.9rem; color: var(--text-muted); }
.workflow-explanation strong { color: var(--text); }

/* Full Workflow SVG */
.workflow-diagram-visual { padding: 2rem 1rem; background: rgba(0,0,0,0.2); border-radius: 10px; margin-bottom: 1.5rem; overflow-x: auto; }
.full-workflow-svg { width: 100%; max-width: 900px; height: auto; min-height: 320px; display: block; margin: 0 auto; }

/* Responsive */
@media (max-width: 768px) {
    .hero { flex-direction: column; padding: 2rem 1.5rem; text-align: center; }
    .hero-content h1 { font-size: 2.2rem; }
    .hero-visual { display: none; }
    .page-inner { padding: 2rem 1.5rem 5rem; }
    .concept-card.wide { grid-column: span 1; }
    .nav-links { display: none; }
    .workflow-diagram { flex-wrap: wrap; justify-content: center; }
    .workflow-row { flex-wrap: wrap; justify-content: center; }
    .tag-grid { grid-template-columns: 1fr; }
}