:root {
    --cream: #fff8ec;
    --paper: #fffdf7;
    --ink: #11223f;
    --muted: #69748a;
    --blue: #173b7a;
    --blue-soft: #eaf0ff;
    --orange: #ff8d3a;
    --purple: #b99cff;
    --purple-soft: #f1eaff;
    --line: rgba(17, 34, 63, .12);
    --shadow: 0 18px 45px rgba(23, 59, 122, .12);
    --radius: 28px;
    --radius-sm: 18px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
    background: radial-gradient(circle at top left, rgba(185,156,255,.28), transparent 30rem), linear-gradient(180deg, var(--cream), #fff 52%, #f7f3ff);
    color: var(--ink);
    line-height: 1.7;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
button, input, textarea { font: inherit; }
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 16px clamp(18px, 4vw, 56px);
    background: rgba(255, 248, 236, .88);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 12px; font-weight: 900; }
.brand-mark {
    display: inline-grid;
    place-items: center;
    width: 48px;
    height: 48px;
    border-radius: 17px;
    background: linear-gradient(135deg, var(--blue), #315aa9 54%, var(--orange));
    color: white;
    letter-spacing: -.04em;
    box-shadow: 0 12px 22px rgba(23,59,122,.18);
}
.brand-text { color: var(--blue); }
.main-nav { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }
.main-nav a {
    padding: 10px 14px;
    border-radius: 999px;
    color: #31405d;
    font-weight: 700;
    transition: background .2s ease, transform .2s ease, color .2s ease;
}
.main-nav a:hover, .main-nav a.active { background: var(--blue); color: white; transform: translateY(-1px); }
.nav-toggle { display: none; border: 0; border-radius: 14px; padding: 10px 13px; background: var(--blue); color: white; }
main { overflow: hidden; }
.container { width: min(1160px, calc(100% - 36px)); margin: 0 auto; }
.hero {
    padding: clamp(48px, 8vw, 88px) 0 42px;
}
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.04fr) minmax(320px, .96fr); gap: clamp(28px, 5vw, 62px); align-items: center; }
.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 13px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: rgba(255,255,255,.72);
    color: var(--blue);
    font-size: 14px;
    font-weight: 800;
}
.eyebrow::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--orange); box-shadow: 0 0 0 6px rgba(255,141,58,.15); }
h1, h2, h3 { line-height: 1.18; margin: 0; letter-spacing: -.03em; }
h1 { font-size: clamp(40px, 7vw, 78px); margin-top: 20px; }
h2 { font-size: clamp(28px, 4vw, 44px); }
h3 { font-size: 22px; }
p { margin: 0; color: var(--muted); }
.lead { font-size: clamp(18px, 2vw, 22px); margin-top: 20px; max-width: 720px; color: #43506a; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 28px; }
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 13px 18px;
    border-radius: 999px;
    border: 1px solid transparent;
    font-weight: 900;
    cursor: pointer;
    transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 16px 28px rgba(23,59,122,.15); }
.btn.primary { background: var(--blue); color: white; }
.btn.secondary { background: white; border-color: var(--line); color: var(--blue); }
.btn.soft { background: var(--purple-soft); color: var(--blue); }
.hero-card {
    position: relative;
    border-radius: var(--radius);
    background: rgba(255,255,255,.78);
    border: 1px solid var(--line);
    padding: 22px;
    box-shadow: var(--shadow);
}
.float-badge {
    position: absolute;
    right: 18px;
    top: 18px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 13px;
    border-radius: 999px;
    background: #fff;
    color: var(--blue);
    font-weight: 900;
    box-shadow: 0 12px 28px rgba(23,59,122,.13);
}
.float-badge span { color: var(--orange); }
.section { padding: clamp(42px, 6vw, 76px) 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 28px; margin-bottom: 26px; }
.section-head p { max-width: 680px; margin-top: 10px; }
.kicker { color: var(--orange); font-weight: 900; letter-spacing: .06em; font-size: 13px; text-transform: uppercase; }
.grid { display: grid; gap: 22px; }
.grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.card {
    background: rgba(255,255,255,.78);
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    padding: 22px;
    box-shadow: 0 12px 30px rgba(23,59,122,.08);
}
.card h3 { margin: 12px 0 8px; }
.card .icon { width: 54px; height: 54px; border-radius: 18px; background: var(--blue-soft); display: grid; place-items: center; color: var(--blue); font-size: 26px; }
.playlist-card { overflow: hidden; padding: 0; }
.playlist-card .cover { min-height: 220px; background: var(--purple-soft); }
.playlist-card .content { padding: 22px; }
.tags { display: flex; gap: 8px; flex-wrap: wrap; margin: 14px 0; }
.tag { padding: 6px 10px; border-radius: 999px; background: var(--blue-soft); color: var(--blue); font-size: 13px; font-weight: 800; }
.stats { display: flex; gap: 12px; flex-wrap: wrap; color: var(--muted); font-size: 14px; margin-top: 16px; }
.stat { display: inline-flex; align-items: center; gap: 5px; }
.interactions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.pill-btn {
    border: 1px solid var(--line);
    background: #fff;
    border-radius: 999px;
    padding: 9px 12px;
    cursor: pointer;
    color: var(--blue);
    font-weight: 800;
}
.pill-btn.is-on { background: var(--blue); color: #fff; border-color: var(--blue); }
.topic-list { display: grid; gap: 14px; }
.topic {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 18px;
    align-items: center;
    padding: 18px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--line);
    background: rgba(255,255,255,.82);
}
.topic strong { display: block; margin-bottom: 4px; }
.topic .hot { color: var(--orange); font-weight: 900; }
.score-box { display: flex; align-items: center; gap: 18px; }
.score {
    width: 82px;
    height: 82px;
    border-radius: 24px;
    background: linear-gradient(135deg, var(--orange), #ffc06f);
    color: white;
    display: grid;
    place-items: center;
    font-size: 30px;
    font-weight: 950;
    box-shadow: 0 14px 30px rgba(255,141,58,.28);
}
.stars { color: #ffad33; letter-spacing: 2px; }
.bubble {
    position: relative;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 24px 24px 24px 8px;
    padding: 18px;
}
.bubble::after { content: ""; position: absolute; left: 18px; bottom: -9px; border-width: 10px 10px 0 0; border-style: solid; border-color: #fff transparent transparent transparent; }
.avatar-row { display: flex; align-items: center; gap: 12px; margin-top: 16px; }
.avatar { width: 42px; height: 42px; border-radius: 50%; background: linear-gradient(135deg, var(--purple), var(--orange)); display: grid; place-items: center; color: white; font-weight: 900; }
.feed { display: grid; gap: 16px; }
.feed-item { display: grid; grid-template-columns: 48px 1fr; gap: 14px; padding: 16px; border-radius: var(--radius-sm); background: #fff; border: 1px solid var(--line); }
.challenge {
    display: grid;
    grid-template-columns: minmax(280px, .95fr) minmax(0, 1.05fr);
    gap: 28px;
    align-items: center;
    background: linear-gradient(135deg, #11223f, #173b7a 58%, #6f5cc6);
    color: white;
    border-radius: var(--radius);
    padding: clamp(24px, 4vw, 42px);
    box-shadow: var(--shadow);
}
.challenge p, .challenge .kicker { color: rgba(255,255,255,.78); }
.challenge .tag { background: rgba(255,255,255,.15); color: white; }
.cta-panel {
    text-align: center;
    background: linear-gradient(135deg, rgba(255,141,58,.16), rgba(185,156,255,.23));
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: clamp(28px, 6vw, 58px);
}
.faq { display: grid; gap: 12px; }
details {
    background: rgba(255,255,255,.82);
    border: 1px solid var(--line);
    border-radius: 18px;
    padding: 16px 18px;
}
summary { cursor: pointer; font-weight: 900; color: var(--blue); }
details p { margin-top: 10px; }
.page-hero { padding: clamp(42px, 7vw, 78px) 0 30px; }
.page-hero .lead { max-width: 820px; }
.feature-row { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; align-items: center; }
.panel {
    border-radius: var(--radius);
    padding: clamp(24px, 4vw, 36px);
    border: 1px solid var(--line);
    background: rgba(255,255,255,.76);
    box-shadow: var(--shadow);
}
.timeline { display: grid; gap: 16px; counter-reset: step; }
.timeline .step { position: relative; padding-left: 58px; }
.timeline .step::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: 0;
    top: 2px;
    width: 38px;
    height: 38px;
    display: grid;
    place-items: center;
    border-radius: 14px;
    background: var(--orange);
    color: white;
    font-weight: 900;
}
.form {
    display: grid;
    gap: 14px;
}
.form label { display: grid; gap: 6px; font-weight: 900; color: var(--blue); }
.form input, .form textarea, .form select {
    width: 100%;
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 13px 14px;
    background: #fff;
    color: var(--ink);
}
.form textarea { min-height: 130px; resize: vertical; }
.notice {
    padding: 14px 16px;
    border-radius: 18px;
    background: var(--blue-soft);
    color: var(--blue);
    font-weight: 800;
}
.empty-note { font-size: 14px; color: var(--muted); }
.site-footer {
    margin-top: 40px;
    background: #0f1e38;
    color: #fff;
    padding: 40px clamp(18px, 4vw, 56px) 22px;
}
.site-footer p { color: rgba(255,255,255,.72); margin-top: 8px; }
.footer-grid { display: grid; grid-template-columns: 1.2fr .9fr 1.1fr; gap: 24px; max-width: 1160px; margin: 0 auto; }
.footer-bottom { max-width: 1160px; margin: 28px auto 0; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.14); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; color: rgba(255,255,255,.7); }
@media (max-width: 920px) {
    .hero-grid, .challenge, .feature-row { grid-template-columns: 1fr; }
    .grid.three { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .footer-grid { grid-template-columns: 1fr; }
    .nav-toggle { display: inline-flex; }
    .main-nav {
        position: absolute;
        top: calc(100% + 1px);
        left: 18px;
        right: 18px;
        display: none;
        flex-direction: column;
        align-items: stretch;
        background: #fff;
        border: 1px solid var(--line);
        border-radius: 22px;
        padding: 12px;
        box-shadow: var(--shadow);
    }
    .main-nav.open { display: flex; }
}
@media (max-width: 640px) {
    .site-header { padding: 12px 16px; }
    .brand-text { display: none; }
    .grid.three, .grid.two { grid-template-columns: 1fr; }
    .section-head { display: block; }
    .topic { grid-template-columns: 1fr; }
    .hero-card { padding: 14px; }
    .float-badge { position: static; margin-bottom: 12px; width: max-content; }
    .score-box { align-items: flex-start; }
}