/* ===== 我在AI - 移动端优先响应式样式 ===== */

:root {
    --primary: #4f46e5;
    --secondary: #06b6d4;
    --accent: #8b5cf6;
    --gradient: linear-gradient(135deg, #4f46e5 0%, #06b6d4 100%);
    --gradient-soft: linear-gradient(135deg, #eef2ff 0%, #ecfeff 100%);

    --text: #0f172a;
    --text-light: #475569;
    --text-muted: #94a3b8;
    --bg: #ffffff;
    --bg-light: #f8fafc;
    --bg-alt: #f1f5f9;
    --border: #e2e8f0;
    --border-light: #f1f5f9;

    --radius: 16px;
    --radius-sm: 10px;
    --radius-lg: 24px;
    --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
    --shadow: 0 4px 16px rgba(15, 23, 42, 0.06);
    --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 16px 40px rgba(79, 70, 229, 0.15);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);

    --safe-top: env(safe-area-inset-top, 0px);
    --safe-bottom: env(safe-area-inset-bottom, 0px);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
    scroll-padding-top: 70px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }

.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ===== Header ===== */
.site-header {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: 0 1px 2px rgba(15, 23, 42, 0.05);
    transition: var(--transition);
}
.header-inner {
    height: 60px;
    display: flex; align-items: center; justify-content: space-between;
}
.logo {
    display: flex; align-items: center; gap: 10px;
    font-size: 1.25rem; font-weight: 700;
    background: var(--gradient); -webkit-background-clip: text;
    background-clip: text; -webkit-text-fill-color: transparent;
}
.logo-icon {
    width: 38px; height: 38px; border-radius: 11px;
    background: var(--gradient);
    display: flex; align-items: center; justify-content: center;
    overflow: hidden; flex-shrink: 0;
}
.logo-icon img { width: 100%; height: 100%; object-fit: cover; }
.main-nav { display: flex; align-items: center; gap: 28px; }
.main-nav a {
    font-size: 0.95rem; font-weight: 500; color: var(--text-light);
    transition: var(--transition);
}
.main-nav a:hover { color: var(--primary); }
.nav-toggle {
    display: none; width: 40px; height: 40px;
    align-items: center; justify-content: center;
    color: var(--text); border-radius: 10px;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    padding: 13px 28px; font-size: 0.95rem; font-weight: 600;
    border-radius: 999px; transition: var(--transition);
    min-height: 44px; cursor: pointer;
}
.btn-primary { background: var(--gradient); color: #fff; box-shadow: 0 4px 16px rgba(79, 70, 229, 0.3); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(79, 70, 229, 0.4); }
.btn-secondary { background: var(--bg-alt); color: var(--text); }
.btn-secondary:hover { background: var(--border); }
.btn-large { padding: 16px 36px; font-size: 1.05rem; }
.btn-block { width: 100%; }

/* ===== Hero ===== */
.hero {
    padding: 120px 0 60px;
    background: var(--gradient-soft);
    position: relative; overflow: hidden;
}
.hero::before {
    content: ''; position: absolute; top: -200px; right: -200px;
    width: 500px; height: 500px; border-radius: 50%;
    background: radial-gradient(circle, rgba(79, 70, 229, 0.12) 0%, transparent 70%);
}
.hero-content { position: relative; text-align: center; max-width: 760px; margin: 0 auto; }
.hero-badge {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 6px 16px; background: rgba(79, 70, 229, 0.1);
    color: var(--primary); font-size: 0.85rem; font-weight: 600;
    border-radius: 999px; margin-bottom: 24px;
}
.hero-title {
    font-size: 2.6rem; font-weight: 800; line-height: 1.2;
    margin-bottom: 20px; letter-spacing: -0.02em;
}
.hero-title span {
    background: var(--gradient); -webkit-background-clip: text;
    background-clip: text; -webkit-text-fill-color: transparent;
}
.hero-subtitle {
    font-size: 1.1rem; color: var(--text-light); line-height: 1.7;
    margin-bottom: 24px;
}
.hero-keywords {
    display: flex; flex-wrap: wrap; justify-content: center; gap: 10px;
    margin-bottom: 36px;
}
.hero-keywords span {
    padding: 6px 14px; background: #fff; border: 1px solid var(--border);
    border-radius: 999px; font-size: 0.85rem; color: var(--text-light);
    box-shadow: var(--shadow-sm);
}
.hero-actions {
    display: flex; gap: 16px; justify-content: center; flex-wrap: wrap;
    margin-bottom: 40px;
}
.hero-stats {
    display: flex; gap: 32px; justify-content: center; flex-wrap: wrap;
    margin-bottom: 40px;
}
.hero-stat-number {
    font-size: 1.6rem; font-weight: 800; color: var(--primary);
}
.hero-stat-label { font-size: 0.85rem; color: var(--text-muted); }
.hero-showcase { margin-top: 20px; }
.hero-showcase-img {
    max-width: 300px; margin: 0 auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

/* ===== Section ===== */
.section { padding: 70px 0; }
.section-alt { background: var(--bg-light); }
.section-header { text-align: center; max-width: 680px; margin: 0 auto 48px; }
.section-title {
    font-size: 2rem; font-weight: 800; margin-bottom: 14px; letter-spacing: -0.01em;
}
.section-subtitle { font-size: 1.05rem; color: var(--text-light); }

/* ===== Features Grid ===== */
.features-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px;
}
.feature-card {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius); padding: 32px 26px;
    transition: var(--transition); box-shadow: var(--shadow-sm);
}
.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: var(--primary); }
.feature-icon {
    width: 56px; height: 56px; border-radius: 14px;
    background: var(--gradient-soft); color: var(--primary);
    display: flex; align-items: center; justify-content: center;
    font-size: 1.6rem; margin-bottom: 18px;
}
.feature-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 10px; }
.feature-card p { font-size: 0.95rem; color: var(--text-light); line-height: 1.7; }

/* ===== Characters Grid ===== */
.characters-grid {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px;
}
.character-card {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius); padding: 26px 18px; text-align: center;
    transition: var(--transition); box-shadow: var(--shadow-sm);
}
.character-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.character-avatar {
    width: 72px; height: 72px; border-radius: 50%;
    margin: 0 auto 14px; display: flex; align-items: center; justify-content: center;
    font-size: 1.6rem; font-weight: 700; color: #fff;
}
.character-card h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: 4px; }
.character-type { font-size: 0.85rem; color: var(--text-muted); }
.character-screenshot {
    grid-column: 1 / -1; margin-top: 12px; text-align: center;
}
.character-screenshot img {
    max-height: 420px; margin: 0 auto; border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.character-screenshot-caption {
    margin-top: 12px; font-size: 0.9rem; color: var(--text-muted);
}

/* ===== Scenarios Grid ===== */
.scenarios-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px;
}
.scenario-card {
    background: #fff; border-radius: var(--radius); overflow: hidden;
    box-shadow: var(--shadow-sm); transition: var(--transition);
    border: 1px solid var(--border-light);
}
.scenario-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.scenario-banner {
    height: 140px; display: flex; align-items: center; justify-content: center;
    font-size: 3rem;
}
.scenario-banner img { width: 100%; height: 100%; object-fit: cover; }
.scenario-content { padding: 24px; }
.scenario-content h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 8px; }
.scenario-content p { font-size: 0.92rem; color: var(--text-light); line-height: 1.7; }

/* ===== Tutorial Steps ===== */
.tutorial-steps {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
    counter-reset: step;
}
.tutorial-step {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius); padding: 32px 24px 26px;
    position: relative; box-shadow: var(--shadow-sm);
}
.tutorial-step::before {
    counter-increment: step; content: counter(step);
    position: absolute; top: -18px; left: 24px;
    width: 40px; height: 40px; border-radius: 50%;
    background: var(--gradient); color: #fff;
    display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 1.1rem; box-shadow: var(--shadow-lg);
}
.tutorial-step h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; }
.tutorial-step p { font-size: 0.92rem; color: var(--text-light); line-height: 1.7; }
.tutorial-showcase { margin-top: 40px; text-align: center; }
.tutorial-showcase img {
    max-height: 400px; margin: 0 auto; border-radius: var(--radius);
    box-shadow: var(--shadow);
}

/* ===== Comparison Grid ===== */
.comparison-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px;
}
.comparison-card {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius); padding: 32px 26px;
    transition: var(--transition); box-shadow: var(--shadow-sm);
}
.comparison-card.featured {
    border: 2px solid var(--primary); transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}
.comparison-icon { font-size: 2.4rem; margin-bottom: 14px; }
.comparison-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 10px; }
.comparison-card p { font-size: 0.92rem; color: var(--text-light); line-height: 1.7; margin-bottom: 14px; }
.comparison-card li { font-size: 0.9rem; padding: 6px 0; color: var(--text-light); border-bottom: 1px solid var(--border-light); }
.comparison-card li:last-child { border-bottom: none; }

/* ===== Testimonials Grid ===== */
.testimonials-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px;
}
.testimonial-card {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius); padding: 28px 24px;
    box-shadow: var(--shadow-sm); transition: var(--transition);
}
.testimonial-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.testimonial-stars { color: #fbbf24; font-size: 1rem; margin-bottom: 14px; }
.testimonial-card h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.testimonial-text { font-size: 0.92rem; color: var(--text-light); line-height: 1.8; margin-bottom: 16px; }
.testimonial-user { display: flex; align-items: center; gap: 10px; }
.user-avatar {
    width: 42px; height: 42px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-weight: 700; font-size: 0.95rem;
}
.testimonial-user strong { font-size: 0.92rem; display: block; }
.testimonial-user span { font-size: 0.8rem; color: var(--text-muted); }

/* ===== Download Section ===== */
.download-section {
    padding: 70px 0; background: var(--gradient); color: #fff;
    text-align: center;
}
.download-section h2 { font-size: 2rem; font-weight: 800; margin-bottom: 14px; }
.download-section p { font-size: 1.05rem; opacity: 0.95; margin-bottom: 32px; }
.download-buttons {
    display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 24px;
}
.download-btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 32px; background: #fff; color: var(--primary);
    font-weight: 700; font-size: 1rem; border-radius: 999px;
    transition: var(--transition); min-height: 44px;
}
.download-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,0.2); }
.download-info {
    display: flex; gap: 24px; justify-content: center; flex-wrap: wrap;
    font-size: 0.9rem; opacity: 0.9;
}

/* ===== FAQ ===== */
.faq-list { max-width: 820px; margin: 0 auto; }
.faq-item {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius-sm); margin-bottom: 12px;
    overflow: hidden; transition: var(--transition);
}
.faq-item.active { box-shadow: var(--shadow); border-color: var(--primary); }
.faq-question {
    width: 100%; padding: 18px 20px; display: flex;
    justify-content: space-between; align-items: center;
    font-size: 1rem; font-weight: 600; text-align: left; color: var(--text);
    min-height: 44px;
}
.faq-icon { font-size: 1.4rem; color: var(--primary); transition: var(--transition); flex-shrink: 0; }
.faq-item.active .faq-icon { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; }
.faq-item.active .faq-answer { max-height: 500px; }
.faq-answer-inner { padding: 0 20px 18px; font-size: 0.92rem; color: var(--text-light); line-height: 1.8; }

/* ===== Keywords Cloud ===== */
.keywords-section { padding: 50px 0; background: var(--bg-alt); }
.keywords-title { text-align: center; font-size: 1.3rem; font-weight: 700; margin-bottom: 24px; }
.keywords-cloud { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; max-width: 900px; margin: 0 auto; }
.keywords-cloud a {
    padding: 8px 16px; background: #fff; border: 1px solid var(--border);
    border-radius: 999px; font-size: 0.88rem; color: var(--text-light);
    transition: var(--transition);
}
.keywords-cloud a:hover { background: var(--gradient); color: #fff; border-color: transparent; }

/* ===== Footer ===== */
.site-footer { background: #0f172a; color: #cbd5e1; padding: 50px 0 30px; }
.footer-grid {
    display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 32px;
}
.footer-brand {
    display: flex; align-items: center; gap: 10px;
    font-size: 1.2rem; font-weight: 700; color: #fff; margin-bottom: 14px;
}
.footer-brand .logo-icon { width: 34px; height: 34px; }
.footer-desc { font-size: 0.9rem; line-height: 1.7; margin-bottom: 10px; }
.footer-col h4 { color: #fff; font-size: 1rem; margin-bottom: 14px; }
.footer-col a { display: block; padding: 6px 0; font-size: 0.9rem; color: #94a3b8; transition: var(--transition); }
.footer-col a:hover { color: #fff; }
.footer-bottom {
    border-top: 1px solid #1e293b; padding-top: 20px;
    text-align: center; font-size: 0.85rem; color: #64748b;
}

/* ===== Mobile Nav ===== */
.mobile-nav {
    display: none; position: fixed; bottom: 0; left: 0; right: 0;
    background: #fff; box-shadow: 0 -2px 20px rgba(0,0,0,0.08);
    z-index: 998; padding: 8px 0;
    padding-bottom: calc(8px + var(--safe-bottom));
}
.mobile-nav-list { display: flex; justify-content: space-around; align-items: center; }
.mobile-nav-item {
    display: flex; flex-direction: column; align-items: center; gap: 2px;
    font-size: 0.72rem; color: var(--text-muted); padding: 6px 12px;
    transition: var(--transition); min-height: 44px; justify-content: center;
}
.mobile-nav-item.active { color: var(--primary); }
.mobile-nav-icon { font-size: 1.25rem; }
.mobile-nav-download {
    background: var(--gradient); color: #fff;
    border-radius: 14px; padding: 8px 14px;
}
.mobile-nav-download.active { color: #fff; }
.mobile-nav-download .mobile-nav-icon { font-size: 1.15rem; }

/* ===== FAB ===== */
.fab-download {
    display: flex; position: fixed; right: 20px; bottom: 100px;
    width: 56px; height: 56px; background: var(--gradient); color: #fff;
    border-radius: 50%; align-items: center; justify-content: center;
    box-shadow: 0 6px 24px rgba(79, 70, 229, 0.5);
    z-index: 997; font-size: 1.5rem; transition: var(--transition);
}
.fab-download:active { transform: scale(0.92); }

/* ===== Download Page ===== */
.download-hero {
    padding: 130px 0 60px; background: var(--gradient-soft); text-align: center;
}
.download-hero h1 { font-size: 2.4rem; font-weight: 800; margin-bottom: 16px; }
.download-card {
    max-width: 560px; margin: 0 auto; background: #fff;
    border-radius: var(--radius-lg); padding: 36px 28px;
    box-shadow: var(--shadow-lg);
}
.download-card h2 { font-size: 1.5rem; font-weight: 800; margin-bottom: 8px; }
.version-info { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 24px; }
.btn-download-large {
    display: block; width: 100%; text-align: center;
    padding: 18px; background: var(--gradient); color: #fff;
    font-weight: 700; font-size: 1.1rem; border-radius: 999px;
    transition: var(--transition); margin-bottom: 24px;
}
.btn-download-large:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.download-features {
    display: flex; gap: 10px; flex-wrap: wrap; justify-content: center;
}
.download-feature {
    padding: 6px 14px; background: var(--bg-alt); border-radius: 999px;
    font-size: 0.85rem; color: var(--text-light);
}

/* ===== Install Steps ===== */
.install-steps {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px;
    max-width: 1000px; margin: 40px auto;
}
.install-step {
    background: #fff; border: 1px solid var(--border-light);
    border-radius: var(--radius); padding: 28px 24px; text-align: center;
    box-shadow: var(--shadow-sm);
}
.install-step-number {
    width: 48px; height: 48px; border-radius: 50%;
    background: var(--gradient-soft); color: var(--primary);
    display: flex; align-items: center; justify-content: center;
    font-size: 1.3rem; font-weight: 800; margin: 0 auto 16px;
}
.install-step h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; }
.install-step p { font-size: 0.9rem; color: var(--text-light); line-height: 1.7; }

/* ===== About Content ===== */
.about-content {
    max-width: 820px; margin: 0 auto;
    font-size: 0.98rem; line-height: 1.85; color: var(--text-light);
}
.about-content p { margin-bottom: 16px; }
.about-content p:last-child { margin-bottom: 0; }
.about-content strong { color: var(--primary); font-weight: 700; }

/* ===== CTA Button ===== */
.cta-btn { font-size: 1.15rem; padding: 20px 50px; }

/* ===== Animation ===== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
.animate { animation: fadeInUp 0.6s ease forwards; }

/* ===== Print ===== */
@media print {
    .site-header, .mobile-nav, .fab-download, .site-footer { display: none; }
    body { padding: 0; }
}

/* ===== Desktop / Tablet (>= 769px) — defaults above are desktop ===== */

/* ===== Tablet ===== */
@media (max-width: 1024px) {
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .characters-grid { grid-template-columns: repeat(3, 1fr); }
    .scenarios-grid { grid-template-columns: repeat(2, 1fr); }
    .comparison-grid { grid-template-columns: repeat(2, 1fr); }
    .testimonials-grid { grid-template-columns: repeat(2, 1fr); }
    .tutorial-steps { grid-template-columns: repeat(2, 1fr); }
    .install-steps { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 2fr 1fr 1fr; }
    .hero-title { font-size: 2.2rem; }
}

/* ===== Mobile ===== */
@media (max-width: 768px) {
    .container { padding: 0 16px; }

    /* Header */
    .header-inner { height: 56px; }
    .logo { font-size: 1.1rem; }
    .logo-icon { width: 34px; height: 34px; border-radius: 10px; }
    .main-nav { display: none; }
    .nav-toggle { display: flex; width: 38px; height: 38px; }

    /* Hero */
    .hero { padding: 100px 0 40px; }
    .hero-title { font-size: 1.65rem; line-height: 1.35; }
    .hero-subtitle { font-size: 0.92rem; line-height: 1.7; }
    .hero-actions { flex-direction: column; align-items: stretch; gap: 12px; }
    .hero-actions .btn { width: 100%; }
    .hero-keywords { gap: 6px; margin-bottom: 28px; }
    .hero-keywords span { font-size: 0.78rem; padding: 4px 12px; }
    .hero-stats { gap: 14px; flex-wrap: wrap; justify-content: center; }
    .hero-stat { flex: 1 1 40%; min-width: 120px; }
    .hero-stat-number { font-size: 1.3rem; }
    .hero-stat-label { font-size: 0.72rem; }
    .hero-showcase { margin-top: 28px; }
    .hero-showcase-img { max-width: 220px; }

    /* Sections */
    .section { padding: 40px 0; }
    .section-header { margin-bottom: 28px; }
    .section-title { font-size: 1.4rem; }
    .section-subtitle { font-size: 0.9rem; }

    /* Grids */
    .features-grid { grid-template-columns: 1fr; gap: 14px; }
    .characters-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .scenarios-grid { grid-template-columns: 1fr; gap: 14px; }
    .tutorial-steps { grid-template-columns: 1fr; gap: 24px; }
    .comparison-grid { grid-template-columns: 1fr; gap: 14px; }
    .testimonials-grid { grid-template-columns: 1fr; gap: 14px; }
    .install-steps { grid-template-columns: 1fr; gap: 20px; }
    .comparison-card.featured { transform: none; }

    /* Cards */
    .feature-card { padding: 24px 20px; }
    .feature-icon { width: 48px; height: 48px; font-size: 1.3rem; margin-bottom: 16px; }
    .feature-card h3 { font-size: 1.08rem; }
    .feature-card p { font-size: 0.9rem; }
    .testimonial-card { padding: 24px 20px; }

    /* Character card */
    .character-card { padding: 20px 14px; }
    .character-avatar { width: 64px; height: 64px; font-size: 1.4rem; margin-bottom: 12px; }
    .character-card h4 { font-size: 0.95rem; }
    .character-type { font-size: 0.78rem; }
    .character-screenshot img { max-height: 300px; border-radius: var(--radius); }
    .character-screenshot-caption { font-size: 0.82rem; }

    /* Scenario card */
    .scenario-banner { height: 180px; }
    .scenario-content { padding: 20px; }
    .scenario-content h3 { font-size: 1.05rem; }
    .scenario-content p { font-size: 0.88rem; }

    /* Tutorial */
    .tutorial-step { padding: 28px 20px 24px; }
    .tutorial-step::before { width: 36px; height: 36px; font-size: 1rem; top: -18px; }
    .tutorial-step h3 { font-size: 1rem; }
    .tutorial-step p { font-size: 0.88rem; }
    .tutorial-showcase img { max-height: 280px; }

    /* Comparison */
    .comparison-card { padding: 24px 20px; }
    .comparison-icon { font-size: 2rem; margin-bottom: 12px; }
    .comparison-card h3 { font-size: 1.05rem; margin-bottom: 8px; }
    .comparison-card li { font-size: 0.85rem; padding: 6px 0; }

    /* Testimonial */
    .testimonial-stars { font-size: 0.95rem; margin-bottom: 12px; }
    .testimonial-text { font-size: 0.88rem; line-height: 1.75; }
    .user-avatar { width: 38px; height: 38px; font-size: 0.85rem; }

    /* Footer */
    .footer-grid { grid-template-columns: 1fr; gap: 24px; }
    .site-footer { padding: 32px 0 88px; }
    .footer-col h4 { margin-bottom: 14px; }
    .footer-col a { padding: 5px 0; font-size: 0.88rem; }
    .footer-desc { font-size: 0.88rem; }
    .footer-brand { font-size: 1.1rem; }
    .footer-brand .logo-icon { width: 30px; height: 30px; }

    /* Mobile Nav */
    .mobile-nav { display: block; }
    .mobile-nav-list { gap: 2px; }
    .mobile-nav-item {
        font-size: 0.7rem; padding: 6px 6px; min-width: 0;
        min-height: 44px; justify-content: center;
    }
    .mobile-nav-icon { font-size: 1.2rem; }
    .mobile-nav-download { padding: 6px 10px; border-radius: 10px; }
    body { padding-bottom: calc(64px + var(--safe-bottom)); }

    /* FAB */
    .fab-download { width: 52px; height: 52px; right: 14px; bottom: 88px; }

    /* Download Section */
    .download-section { padding: 40px 0; }
    .download-section h2 { font-size: 1.4rem; }
    .download-buttons { flex-direction: column; align-items: stretch; gap: 12px; }
    .download-btn { width: 100%; justify-content: center; padding: 14px 24px; font-size: 0.95rem; }
    .download-info { gap: 12px; font-size: 0.82rem; flex-direction: column; align-items: center; }

    /* Download Card */
    .download-card { padding: 28px 22px; margin: 0 12px; }
    .download-card h2 { font-size: 1.25rem; }
    .version-info { font-size: 0.82rem; margin-bottom: 20px; }
    .btn-download-large { padding: 16px; font-size: 1rem; }

    /* Install Steps */
    .install-steps { margin: 32px 0; }
    .install-step { padding: 24px 20px; }
    .install-step-number { width: 40px; height: 40px; font-size: 1rem; margin-bottom: 12px; }
    .install-step h3 { font-size: 1.05rem; margin-bottom: 6px; }
    .install-step p { font-size: 0.88rem; }

    /* FAQ */
    .faq-question { font-size: 0.9rem; padding: 16px; }
    .faq-answer-inner { padding: 0 16px 16px; font-size: 0.86rem; line-height: 1.75; }

    /* Keywords */
    .keywords-cloud { gap: 8px; }
    .keywords-cloud a { padding: 6px 14px; font-size: 0.82rem; }

    /* Buttons */
    .btn { padding: 14px 24px; font-size: 0.95rem; min-height: 44px; }
    .btn-large { padding: 16px 28px; font-size: 1rem; }
    .cta-btn { font-size: 1rem; padding: 16px 32px; }

    /* About Content */
    .about-content { font-size: 0.92rem; line-height: 1.8; }
    .about-content p { margin-bottom: 14px; }

    /* Download Hero */
    .download-hero { padding: 100px 0 40px; }
    .download-hero h1 { font-size: 1.65rem; }

    /* Touch Optimizations */
    *, *::before, *::after {
        -webkit-tap-highlight-color: transparent;
        -webkit-touch-callout: none;
    }
    .btn:active { transform: scale(0.97); transition: transform 0.1s ease; }
    .mobile-nav-item:active { transform: scale(0.9); transition: transform 0.1s ease; }
    .faq-question:active { background: var(--bg-light); }
    .feature-card:active, .character-card:active, .scenario-card:active,
    .testimonial-card:active, .comparison-card:active {
        transform: scale(0.98); transition: transform 0.1s ease;
    }
    section[id], .section[id], .download-section[id] { scroll-margin-top: 60px; }
}

/* ===== Small Mobile ===== */
@media (max-width: 375px) {
    .characters-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .character-avatar { width: 56px; height: 56px; font-size: 1.2rem; }
    .character-card { padding: 18px 12px; }

    .mobile-nav-item { font-size: 0.66rem; padding: 4px 4px; }
    .mobile-nav-icon { font-size: 1.05rem; }
    .mobile-nav-download { padding: 4px 8px; }

    .hero-title { font-size: 1.4rem; }
    .hero-keywords { gap: 4px; }
    .hero-keywords span { font-size: 0.72rem; padding: 3px 10px; }
    .hero-showcase-img { max-width: 180px; }

    .container { padding: 0 14px; }
    .section-title { font-size: 1.25rem; }
    .scenario-banner { height: 150px; }

    .about-content { font-size: 0.88rem; line-height: 1.75; }
    .cta-btn { padding: 14px 24px; font-size: 0.95rem; }
    .hero-stat { min-width: 100px; }
}

/* ===== Dark Mode ===== */
@media (prefers-color-scheme: dark) {
    :root {
        --text: #f1f5f9; --text-light: #cbd5e1; --text-muted: #94a3b8;
        --bg: #0f172a; --bg-light: #1e293b; --bg-alt: #1e293b;
        --border: #334155; --border-light: #1e293b;
    }
    .site-header { background: rgba(15, 23, 42, 0.95); }
    .feature-card, .character-card, .scenario-card,
    .testimonial-card, .comparison-card, .tutorial-step,
    .download-card, .faq-item, .install-step { background: #1e293b; border-color: #334155; }
    .faq-question:active { background: #334155; }
    .keywords-cloud a { background: #1e293b; border-color: #334155; color: #cbd5e1; }
    .mobile-nav { background: #0f172a; }
    .hero-keywords span { background: #1e293b; }
    .download-feature { background: #1e293b; }
}