/* ============================================
   Comment Timeline for YouTube - Landing Page
   ============================================ */

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

:root {
    --primary: #4285f4;
    --primary-dark: #1a73e8;
    --primary-light: #e8f0fe;
    --accent: #ea4335;
    --success: #34a853;
    --warning: #fbbc05;

    --bg-dark: #0a0a0f;
    --bg-card: #12121a;
    --bg-elevated: #1a1a25;

    --text-primary: #ffffff;
    --text-secondary: #a8a8b3;
    --text-muted: #6b6b7b;

    --gradient-primary: linear-gradient(135deg, #4285f4 0%, #34a853 50%, #fbbc05 100%);
    --gradient-hero: linear-gradient(180deg, #0a0a0f 0%, #12121a 100%);
    --gradient-glow: radial-gradient(ellipse at center, rgba(66, 133, 244, 0.15) 0%, transparent 70%);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 60px rgba(66, 133, 244, 0.3);

    --font-primary: 'Inter', 'Noto Sans JP', system-ui, sans-serif;

    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    color: inherit;
    text-decoration: none;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    padding: 16px 40px;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 18px;
    margin-right: auto;
}

.nav-icon {
    font-size: 22px;
    filter: drop-shadow(0 0 8px rgba(66, 133, 244, 0.5));
}

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

.nav-link {
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--text-primary);
}

.nav-cta {
    background: var(--primary);
    color: white !important;
    border-radius: var(--radius-xl);
    margin-left: 8px;
}

.nav-cta:hover {
    background: var(--primary-dark);
}

/* Hero Section */
.hero {
    position: relative;
    min-height: 100vh;
    padding: 120px 40px 80px;
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--gradient-hero);
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 1200px;
    height: 600px;
    background: var(--gradient-glow);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 800px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: rgba(66, 133, 244, 0.1);
    border: 1px solid rgba(66, 133, 244, 0.3);
    border-radius: var(--radius-xl);
    font-size: 14px;
    color: var(--primary);
    margin-bottom: 24px;
    animation: fadeInUp 0.6s ease;
}

.badge-icon {
    animation: sparkle 2s infinite;
}

@keyframes sparkle {

    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }

    50% {
        opacity: 0.6;
        transform: scale(1.1);
    }
}

.hero-title {
    font-size: clamp(36px, 6vw, 64px);
    font-weight: 800;
    line-height: 1.15;
    margin-bottom: 24px;
    animation: fadeInUp 0.6s ease 0.1s both;
}

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

.hero-description {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 36px;
    animation: fadeInUp 0.6s ease 0.2s both;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 48px;
    animation: fadeInUp 0.6s ease 0.3s both;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    font-size: 15px;
    font-weight: 600;
    border-radius: var(--radius-xl);
    transition: all var(--transition-normal);
    cursor: pointer;
    border: none;
}

.btn-icon {
    width: 20px;
    height: 20px;
}

.btn-arrow {
    width: 18px;
    height: 18px;
    transition: transform var(--transition-fast);
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 20px rgba(66, 133, 244, 0.4);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(66, 133, 244, 0.5);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover .btn-arrow {
    transform: translateX(4px);
}

.btn-large {
    padding: 18px 36px;
    font-size: 17px;
}

/* Hero Stats */
.hero-stats {
    display: flex;
    gap: 48px;
    justify-content: center;
    animation: fadeInUp 0.6s ease 0.4s both;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.stat-value {
    font-size: 28px;
}

.stat-label {
    font-size: 13px;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Hero Visual / Mockup */
.hero-visual {
    position: relative;
    z-index: 2;
    margin-top: 60px;
    width: 100%;
    max-width: 900px;
    animation: fadeInUp 0.8s ease 0.5s both;
}

.mockup-container {
    perspective: 1000px;
}

.mockup-browser {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border: 1px solid rgba(255, 255, 255, 0.08);
    transform: rotateX(5deg);
    transition: transform var(--transition-slow);
}

.mockup-browser:hover {
    transform: rotateX(0deg);
}

.browser-header {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 12px 16px;
    background: var(--bg-elevated);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.browser-dots {
    display: flex;
    gap: 8px;
}

.browser-dots span {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
}

.browser-dots span:nth-child(1) {
    background: #ff5f57;
}

.browser-dots span:nth-child(2) {
    background: #febc2e;
}

.browser-dots span:nth-child(3) {
    background: #28c840;
}

.browser-url {
    flex: 1;
    padding: 8px 16px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--radius-sm);
    font-size: 13px;
    color: var(--text-muted);
}

.browser-content {
    display: flex;
    gap: 16px;
    padding: 16px;
}

.mock-video {
    flex: 1;
    aspect-ratio: 16/9;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
}

.mock-video-inner {
    text-align: center;
}

.play-button {
    width: 60px;
    height: 60px;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: #1a1a2e;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.mock-sidebar {
    width: 260px;
    flex-shrink: 0;
}

.mock-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-xl);
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.mock-panel {
    background: #ffffff;
    border-radius: var(--radius-md);
    overflow: hidden;
    color: #0f0f0f;
}

.mock-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    padding: 12px 14px;
    font-size: 13px;
    font-weight: 600;
    border-bottom: 1px solid #e5e5e5;
}

.mock-filter {
    padding: 3px 6px;
    font-size: 11px;
    border: 1px solid #e5e5e5;
    border-radius: 4px;
    background: #fff;
    color: #606060;
    cursor: pointer;
}

.mock-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 14px;
    border-bottom: 1px solid #e5e5e5;
    transition: background var(--transition-fast);
}

.mock-item:hover {
    background: #f2f2f2;
}

.mock-item.playing {
    background: #f3f8ff;
    box-shadow: inset 4px 0 0 #065fd4;
}

.mock-time {
    color: #065fd4;
    font-weight: 600;
    font-size: 14px;
    min-width: 50px;
}

.mock-snippet {
    font-size: 13px;
    color: #606060;
}

/* Sections Common */
section {
    padding: 100px 40px;
}

.section-header {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 60px;
}

.section-tag {
    display: inline-block;
    padding: 6px 14px;
    background: rgba(66, 133, 244, 0.1);
    border: 1px solid rgba(66, 133, 244, 0.2);
    border-radius: var(--radius-xl);
    font-size: 12px;
    font-weight: 600;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 16px;
}

.section-title {
    font-size: clamp(28px, 4vw, 42px);
    font-weight: 700;
    margin-bottom: 16px;
}

.section-desc {
    font-size: 17px;
    color: var(--text-secondary);
}

/* Features Section */
.features {
    background: var(--bg-dark);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-lg);
    padding: 32px;
    transition: all var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
    border-color: rgba(66, 133, 244, 0.3);
    box-shadow: 0 8px 30px rgba(66, 133, 244, 0.1);
}

.feature-icon-wrap {
    width: 56px;
    height: 56px;
    background: rgba(66, 133, 244, 0.1);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.feature-icon {
    font-size: 28px;
}

.feature-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
}

.feature-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* How it Works Section */
.how-it-works {
    background: var(--bg-card);
}

.steps {
    max-width: 700px;
    margin: 0 auto;
}

.step {
    display: flex;
    align-items: flex-start;
    gap: 24px;
    padding: 32px;
    background: var(--bg-elevated);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
}

.step:hover {
    border-color: rgba(66, 133, 244, 0.3);
}

.step-number {
    font-size: 48px;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    line-height: 1;
}

.step-content {
    flex: 1;
}

.step-content h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
}

.step-content p {
    font-size: 14px;
    color: var(--text-secondary);
}

.step-visual {
    width: 60px;
    height: 60px;
    background: rgba(66, 133, 244, 0.1);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.step-icon {
    font-size: 28px;
}

.step-connector {
    width: 2px;
    height: 32px;
    background: linear-gradient(to bottom, var(--primary), transparent);
    margin: 0 auto;
}

/* Use Cases Section */
.use-cases {
    background: var(--bg-dark);
}

.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    max-width: 1000px;
    margin: 0 auto;
}

.case-card {
    text-align: center;
    padding: 32px 24px;
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
}

.case-card:hover {
    transform: translateY(-4px);
    border-color: rgba(66, 133, 244, 0.3);
}

.case-emoji {
    font-size: 40px;
    margin-bottom: 16px;
}

.case-card h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
}

.case-card p {
    font-size: 13px;
    color: var(--text-secondary);
}

/* Install Section */
.install {
    background: var(--bg-dark);
    padding: 80px 40px 120px;
}

.install-card {
    position: relative;
    max-width: 700px;
    margin: 0 auto;
    padding: 60px 40px;
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-xl);
    text-align: center;
    overflow: hidden;
}

.install-glow {
    position: absolute;
    top: -100px;
    left: 50%;
    transform: translateX(-50%);
    width: 400px;
    height: 200px;
    background: radial-gradient(ellipse, rgba(66, 133, 244, 0.3) 0%, transparent 70%);
    pointer-events: none;
}

.install-content {
    position: relative;
    z-index: 2;
}

.install-content h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 16px;
}

.install-content>p {
    color: var(--text-secondary);
    margin-bottom: 32px;
}

.install-note {
    margin-top: 24px;
    font-size: 13px;
    color: var(--text-muted);
}

/* Footer */
.footer {
    background: var(--bg-card);
    padding: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    font-size: 15px;
}

.footer-copy {
    font-size: 13px;
    color: var(--text-muted);
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive */
@media (max-width: 900px) {
    .nav {
        padding: 14px 20px;
    }

    .nav-link:not(.nav-cta) {
        display: none;
    }

    .hero {
        padding: 100px 20px 60px;
    }

    .hero-description br {
        display: none;
    }

    .hero-stats {
        gap: 32px;
    }

    .browser-content {
        flex-direction: column;
    }

    .mock-sidebar {
        width: 100%;
    }

    section {
        padding: 60px 20px;
    }

    .step {
        flex-direction: column;
        text-align: center;
    }

    .step-visual {
        align-self: center;
    }
}

@media (max-width: 600px) {
    .hero-title {
        font-size: 28px;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 300px;
        justify-content: center;
    }

    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }

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

    .install-card {
        padding: 40px 24px;
    }
}