:root {
    --bg: #101820;
    --bg-soft: #16222e;
    --ink: #eef3f7;
    --muted: #8fa3b5;
    --line: rgba(238, 243, 247, 0.1);
    --amber: #e89a4c;
    --amber-bright: #ffb45c;
    --teal: #4ec9b0;
    --font-display: "Syne", "Noto Sans SC", sans-serif;
    --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    --max: 1040px;
    --pad: clamp(1.25rem, 4vw, 2rem);
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    color: var(--ink);
    font-family: var(--font-body);
    font-size: 1.02rem;
    line-height: 1.7;
    background: var(--bg);
    overflow-x: hidden;
}

.page-bg {
    position: fixed;
    inset: 0;
    z-index: -1;
    background:
        radial-gradient(900px 520px at 85% -5%, rgba(232, 154, 76, 0.2), transparent 58%),
        radial-gradient(700px 420px at 0% 30%, rgba(78, 201, 176, 0.08), transparent 55%),
        linear-gradient(180deg, #15202a 0%, var(--bg) 38%, #0c1218 100%);
}

.page-bg::after {
    content: "";
    position: absolute;
    inset: 0;
    background:
        linear-gradient(180deg, transparent 0%, transparent 55%, var(--bg) 92%),
        url("../img/hero-atmosphere.svg") top center / min(1400px, 160%) auto no-repeat;
    opacity: 0.55;
    animation: bg-shift 20s ease-in-out infinite alternate;
    pointer-events: none;
}

img {
    max-width: 100%;
    display: block;
}

a {
    color: var(--amber-bright);
    text-decoration-thickness: 1px;
    text-underline-offset: 0.18em;
}

a:hover {
    color: #ffd19a;
}

.site-shell {
    width: min(var(--max), 100% - var(--pad) * 2);
    margin-inline: auto;
}

/* Topbar: 轻导航，不和品牌抢戏 */
.topbar {
    position: sticky;
    top: 0;
    z-index: 20;
    backdrop-filter: blur(12px);
    background: rgba(16, 24, 32, 0.72);
    border-bottom: 1px solid transparent;
}

.topbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    min-height: 3.5rem;
}

.topbar-nav {
    display: flex;
    gap: 1.15rem;
}

.topbar-nav a {
    color: var(--muted);
    text-decoration: none;
    font-size: 0.92rem;
}

.topbar-nav a:hover {
    color: var(--ink);
}

.btn-top {
    min-height: 2.25rem;
    padding: 0.4rem 0.9rem;
    font-size: 0.88rem;
    color: #1a120a;
    background: var(--amber);
    border: none;
    border-radius: 0.15rem;
    text-decoration: none;
    font-family: var(--font-display);
    font-weight: 700;
}

.btn-top:hover {
    color: #1a120a;
    background: var(--amber-bright);
}

/* Hero：内容顶对齐，品牌锁扣适中，不再「半屏真空 + 巨字」 */
.hero {
    position: relative;
    padding: clamp(2.5rem, 6vh, 4rem) 0 clamp(3rem, 7vh, 4.5rem);
}

.hero-inner {
    display: grid;
    align-items: center;
    min-height: min(58vh, 520px);
}

.hero-copy {
    max-width: 34rem;
}

.hero-kicker {
    margin: 0 0 1.1rem;
    color: var(--teal);
    font-family: var(--font-display);
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.hero-brand {
    display: flex;
    align-items: center;
    gap: 0.95rem;
    margin-bottom: 1.1rem;
}

.hero-logo {
    width: 3.75rem;
    height: 3.75rem;
    border-radius: 0.85rem;
    box-shadow: 0 12px 28px rgba(194, 65, 12, 0.35);
    flex-shrink: 0;
}

.hero-brand h1 {
    margin: 0;
    font-family: var(--font-display);
    font-size: clamp(2.4rem, 5.5vw, 3.4rem);
    font-weight: 800;
    line-height: 1;
    letter-spacing: -0.03em;
    color: #fff7ec;
}

.hero-brand h1 em {
    font-style: normal;
    font-weight: 700;
    color: var(--amber-bright);
}

.hero-lead {
    margin: 0 0 1.5rem;
    max-width: 22em;
    font-size: clamp(1.05rem, 2vw, 1.2rem);
    color: var(--muted);
    line-height: 1.65;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 2.85rem;
    padding: 0.65rem 1.2rem;
    border-radius: 0.15rem;
    border: 1px solid transparent;
    font-family: var(--font-display);
    font-size: 0.98rem;
    font-weight: 700;
    text-decoration: none;
    cursor: pointer;
    transition: transform 0.18s ease, background 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

.btn:hover {
    transform: translateY(-1px);
}

.btn-primary {
    color: #1a120a;
    background: linear-gradient(135deg, var(--amber-bright), var(--amber));
    box-shadow: 0 10px 28px rgba(232, 154, 76, 0.28);
}

.btn-primary:hover {
    color: #1a120a;
}

.btn-ghost {
    color: var(--ink);
    border-color: var(--line);
    background: rgba(22, 34, 46, 0.55);
}

.btn-ghost:hover {
    color: #fff;
    border-color: rgba(232, 154, 76, 0.45);
}

.install-note {
    margin: 0.9rem 0 0;
    color: var(--muted);
    font-size: 0.9rem;
    outline: none;
}

.install-note[hidden] {
    display: none !important;
}

html.is-ready .hero-kicker,
html.is-ready .hero-brand,
html.is-ready .hero-lead,
html.is-ready .hero-actions,
html.is-ready .install-note {
    animation: rise-in 0.7s cubic-bezier(0.22, 1, 0.36, 1) both;
}

html.is-ready .hero-brand { animation-delay: 0.06s; }
html.is-ready .hero-lead { animation-delay: 0.12s; }
html.is-ready .hero-actions { animation-delay: 0.18s; }
html.is-ready .install-note { animation-delay: 0.24s; }

@keyframes rise-in {
    from {
        opacity: 0;
        transform: translateY(14px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes bg-shift {
    from { transform: scale(1) translate3d(0, 0, 0); }
    to { transform: scale(1.03) translate3d(-1%, 0.8%, 0); }
}

/* Sections */
.section {
    padding: clamp(3rem, 7vh, 4.5rem) 0;
    border-top: 1px solid var(--line);
}

.section-title {
    margin: 0 0 0.5rem;
    font-family: var(--font-display);
    font-size: clamp(1.55rem, 3.2vw, 2rem);
    font-weight: 750;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.section-desc {
    margin: 0 0 1.75rem;
    max-width: 32ch;
    color: var(--muted);
}

.feature-list,
.steps,
.changelog {
    margin: 0;
    padding: 0;
    list-style: none;
}

.feature-list {
    display: grid;
    gap: 1.5rem;
}

@media (min-width: 800px) {
    .feature-list {
        grid-template-columns: repeat(3, 1fr);
        gap: 2rem;
    }
}

.feature-index {
    display: block;
    margin-bottom: 0.45rem;
    color: var(--amber);
    font-family: var(--font-display);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.1em;
}

.feature-list h3 {
    margin: 0 0 0.4rem;
    font-family: var(--font-display);
    font-size: 1.15rem;
}

.feature-list p {
    margin: 0;
    color: var(--muted);
    font-size: 0.95rem;
}

.steps {
    display: grid;
    gap: 1.35rem;
    counter-reset: step;
}

@media (min-width: 800px) {
    .steps {
        grid-template-columns: repeat(3, 1fr);
        gap: 1.75rem;
    }
}

.steps li::before {
    counter-increment: step;
    content: counter(step, decimal-leading-zero);
    display: block;
    margin-bottom: 0.55rem;
    font-family: var(--font-display);
    font-size: 1.55rem;
    font-weight: 800;
    color: rgba(232, 154, 76, 0.85);
    line-height: 1;
}

.steps strong {
    display: block;
    margin-bottom: 0.3rem;
    font-family: var(--font-display);
    font-size: 1.05rem;
}

.steps span {
    color: var(--muted);
    font-size: 0.95rem;
}

.privacy-panel {
    max-width: 48ch;
}

.privacy-panel p {
    margin: 0 0 0.9rem;
    color: var(--muted);
}

.changelog {
    display: grid;
    gap: 1.1rem;
}

.changelog li {
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--line);
}

.changelog time {
    display: block;
    margin-bottom: 0.2rem;
    color: var(--teal);
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 700;
}

.changelog strong {
    font-family: var(--font-display);
    font-size: 1.05rem;
}

.changelog p {
    margin: 0.25rem 0 0;
    color: var(--muted);
    font-size: 0.95rem;
}

[data-reveal] {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity 0.55s ease, transform 0.55s cubic-bezier(0.22, 1, 0.36, 1);
}

[data-reveal].is-visible {
    opacity: 1;
    transform: none;
}

.footer {
    padding: 1.75rem 0 2.25rem;
    border-top: 1px solid var(--line);
    color: var(--muted);
    font-size: 0.9rem;
}

.footer-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem 1.25rem;
}

.footer p {
    margin: 0;
}

.footer nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.85rem 1.15rem;
}

.footer a {
    color: var(--muted);
    text-decoration: none;
}

.footer a:hover {
    color: var(--amber-bright);
}

@media (max-width: 640px) {
    .topbar-nav {
        gap: 0.85rem;
    }

    .hero-inner {
        min-height: 0;
    }

    .hero-brand {
        align-items: flex-start;
    }

    .hero-logo {
        width: 3.2rem;
        height: 3.2rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }

    .page-bg::after,
    html.is-ready .hero-kicker,
    html.is-ready .hero-brand,
    html.is-ready .hero-lead,
    html.is-ready .hero-actions,
    html.is-ready .install-note,
    [data-reveal] {
        animation: none !important;
        transition: none !important;
        opacity: 1 !important;
        transform: none !important;
    }
}