:root {
    --bg: #fbfaf7;
    --surface: #ffffff;
    --surface-2: #f3f0eb;
    --text: #1c1917;
    --dim: #6b645c;
    --border: #ebe6de;
    --accent: #f23a12;
    --accent-2: #ff7a45;
    --accent-soft: #fff0ea;
    --shadow: 0 24px 60px -24px rgba(60, 40, 20, 0.28);
    --mark: #ffe58a;
    --bezel: #1b1917;

    --font-sans: 'Inter', system-ui, -apple-system, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    --font-serif: 'Fraunces', 'Noto Serif SC', 'Songti SC', Georgia, serif;

    --radius-sm: 10px;
    --radius-md: 18px;
    --radius-lg: 28px;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #131110;
        --surface: #1d1a18;
        --surface-2: #262220;
        --text: #f5f1ec;
        --dim: #a59d94;
        --border: #2e2a26;
        --accent: #ff5a33;
        --accent-soft: #3a1c12;
        --shadow: 0 24px 60px -24px rgba(0, 0, 0, 0.7);
        --mark: #6b5800;
        --bezel: #3a3531;
    }
}

html[data-lang="en"] [lang="zh"],
html[data-lang="zh"] [lang="en"] {
    display: none !important;
}

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

body {
    font-family: var(--font-sans);
    background: var(--bg);
    color: var(--text);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container {
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 24px;
}

h1, h2 {
    font-family: var(--font-serif);
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.15;
}

h1 { font-size: clamp(2.4rem, 5.5vw, 4rem); margin-bottom: 20px; }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.6rem); margin-bottom: 14px; }
h3 { font-size: 1.15rem; font-weight: 600; margin-bottom: 6px; }

.eyebrow {
    display: inline-block;
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    color: var(--accent);
    background: var(--accent-soft);
    padding: 4px 12px;
    border-radius: 999px;
    margin-bottom: 20px;
}

.lead { font-size: 1.15rem; color: var(--dim); max-width: 34em; }
mark { background: var(--mark); color: inherit; padding: 0 2px; border-radius: 3px; }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 22px;
    border-radius: 999px;
    font-weight: 600;
    font-size: 0.95rem;
    border: 1px solid transparent;
    cursor: pointer;
    transition: transform 0.15s, background 0.2s, border-color 0.2s;
    background: none;
    color: inherit;
    font-family: inherit;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--text); color: var(--bg); }
.btn-secondary { border-color: var(--border); background: var(--surface); }
.btn-ghost { padding: 8px 14px; border-color: var(--border); }
.btn-lg { padding: 15px 28px; font-size: 1rem; }
.btn svg { width: 18px; height: 18px; fill: currentColor; }

/* Header */
.site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: color-mix(in srgb, var(--bg) 80%, transparent);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
}
.header-content { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.15rem; }
.logo img { width: 34px; height: 34px; }
.site-header nav { display: flex; align-items: center; gap: 22px; font-size: 0.95rem; }
.site-header nav a:not(.btn) { color: var(--dim); }
.site-header nav a:not(.btn):hover { color: var(--text); }

/* Hero */
.hero { position: relative; padding: 72px 0 96px; overflow: hidden; }
.hero-content { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }
.hero-note { margin-top: 16px; font-size: 0.85rem; color: var(--dim); }
.hero-glow {
    position: absolute;
    inset: -20% -10% auto auto;
    width: 640px;
    height: 640px;
    background: radial-gradient(circle, color-mix(in srgb, var(--accent-2) 22%, transparent), transparent 65%);
    pointer-events: none;
    z-index: -1;
}

/* Phone mockup of the app's library screen */
.phone-wrap { display: flex; justify-content: center; }
.phone {
    width: 300px;
    height: 620px;
    border-radius: 48px;
    border: 10px solid var(--bezel);
    background: var(--surface);
    box-shadow: var(--shadow);
    padding: 38px 16px 0;
    overflow: hidden;
    position: relative;
    font-size: 13px;
    transform: rotate(2deg);
}
.phone::before {
    content: '';
    position: absolute;
    top: 10px;
    left: 50%;
    width: 86px;
    height: 24px;
    margin-left: -43px;
    background: var(--bezel);
    border-radius: 999px;
}
.mock-title { font-size: 26px; font-weight: 800; letter-spacing: -0.02em; margin: 8px 0 10px; }
.mock-search { background: var(--surface-2); border-radius: 12px; padding: 7px 12px; color: var(--dim); margin-bottom: 12px; }
.mock-chips { display: flex; gap: 6px; margin-bottom: 8px; white-space: nowrap; }
.mock-chips span { padding: 4px 12px; border-radius: 999px; background: var(--surface-2); color: var(--dim); }
.mock-chips span.on { background: var(--accent-soft); color: var(--accent); }
.mock-row { display: grid; grid-template-columns: 1fr 54px; gap: 10px; padding: 11px 0; border-bottom: 1px solid var(--border); }
.mock-row b { display: block; font-size: 13.5px; line-height: 1.35; margin-bottom: 3px; }
.mock-row small { color: var(--dim); font-size: 11px; }
.mock-thumb { width: 54px; height: 54px; border-radius: 9px; }
.t1 { background: linear-gradient(135deg, #f7c59f, #e86a3a); }
.t2 { background: linear-gradient(135deg, #b8d8c8, #4b8f73); }
.t3 { background: linear-gradient(135deg, #c7cdf2, #5a64b8); }
.t4 { background: linear-gradient(135deg, #f1e3b3, #c9a227); }
.mock-tabbar {
    position: absolute;
    bottom: 14px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 26px;
    padding: 8px 22px;
    border-radius: 999px;
    background: var(--surface);
    box-shadow: 0 4px 18px rgba(0, 0, 0, 0.12);
    font-size: 11px;
    color: var(--dim);
    white-space: nowrap;
}
.mock-tabbar .on { color: var(--accent); font-weight: 600; }

/* Sections */
section { padding: 96px 0; scroll-margin-top: 68px; }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 56px; }
.section-head p { color: var(--dim); font-size: 1.05rem; }

.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 28px;
    transition: transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.feature-card p { color: var(--dim); font-size: 0.95rem; }
.feature-icon {
    width: 46px;
    height: 46px;
    border-radius: 13px;
    display: grid;
    place-items: center;
    background: var(--accent-soft);
    color: var(--accent);
    margin-bottom: 18px;
}

.steps { background: var(--surface-2); }
.step-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; counter-reset: step; }
.step { counter-increment: step; }
.step::before {
    content: counter(step, decimal-leading-zero);
    display: block;
    font-family: var(--font-serif);
    font-size: 2.6rem;
    color: var(--accent);
    line-height: 1;
    margin-bottom: 14px;
}
.step p { color: var(--dim); }

.quote { text-align: center; }
.quote blockquote {
    font-family: var(--font-serif);
    font-size: clamp(1.5rem, 3vw, 2.2rem);
    line-height: 1.4;
    max-width: 800px;
    margin: 0 auto;
}

.cta { text-align: center; }
.cta-card {
    background: var(--text);
    color: var(--bg);
    border-radius: var(--radius-lg);
    padding: 72px 24px;
}
.cta-card p { opacity: 0.7; margin-bottom: 28px; }
.cta-card .btn-primary { background: var(--bg); color: var(--text); }

/* Footer */
footer { border-top: 1px solid var(--border); padding: 40px 0; font-size: 0.9rem; color: var(--dim); }
.footer-content { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 16px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 20px; }
.footer-links a:hover, .footer-links button:hover { color: var(--text); }
.footer-links button { background: none; border: 0; color: inherit; font: inherit; cursor: pointer; }
.copyright { width: 100%; font-size: 0.8rem; }

/* Policy pages */
.policy { padding: 64px 0 96px; }
.policy-container { max-width: 760px; margin: 0 auto; }
.policy h1 { font-size: clamp(2rem, 4vw, 2.8rem); }
.policy-meta { color: var(--dim); padding-bottom: 20px; margin-bottom: 32px; border-bottom: 1px solid var(--border); }
.policy-section { margin-bottom: 32px; }
.policy-section h2 { font-family: var(--font-sans); font-size: 1.2rem; letter-spacing: 0; margin-bottom: 10px; }
.policy-section p, .policy-section li { color: var(--dim); margin-bottom: 8px; }
.policy-section ul { padding-left: 22px; margin-bottom: 8px; }
.policy-section strong { color: var(--text); }
.policy-section a { color: var(--accent); }

@media (max-width: 860px) {
    .hero { padding-top: 40px; }
    .hero-content { grid-template-columns: 1fr; }
    .phone { transform: none; }
    .feature-grid, .step-grid { grid-template-columns: 1fr; }
    .site-header nav .nav-link { display: none; }
    section { padding: 64px 0; }
    .container { padding: 0 16px; }
}