/* ============================================================
   sk.itworldsk.top — 首页 · 高端品牌 · 沉稳奢感
   暖调中性色系 · 衬线/无衬线混排 · 金铜点缀 · 零外部字体依赖
   ============================================================ */

:root {
    /* 背景层次：深暖近黑 → 面板 → 抬升 */
    --bg:        #14120f;
    --bg-2:      #1b1916;
    --bg-3:      #221f1a;
    --bg-soft:   #1f1c18;

    /* 文字 */
    --text:      #f3ede1;
    --text-2:    #cfc6b5;
    --muted:     #978d7b;
    --faint:     #6d6557;

    /* 金铜点缀 */
    --gold:      #c9a86a;
    --gold-2:    #e7cd95;
    --copper:    #b07a4a;
    --gold-grad: linear-gradient(135deg, #ecd49d 0%, #c9a86a 46%, #a9824c 100%);

    /* 描边 */
    --hair:      rgba(243, 237, 225, 0.09);
    --hair-gold: rgba(201, 168, 106, 0.22);

    /* 尺度 */
    --wrap:      1180px;
    --radius:    18px;
    --ease:      cubic-bezier(0.22, 0.61, 0.36, 1);

    /* 字体栈：拉丁衬线 + 中文宋体系，呈现编辑级优雅 */
    --serif: Georgia, "Times New Roman",
             "Source Han Serif SC", "Source Han Serif CN", "Noto Serif CJK SC",
             "Songti SC", STSong, "SimSun", serif;
    --sans:  -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
             "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue",
             Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--sans);
    font-size: 16px;
    line-height: 1.65;
    font-weight: 400;
    letter-spacing: 0.01em;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    /* 极淡暖色径向底纹，营造氛围 */
    background-image:
        radial-gradient(1200px 600px at 78% -8%, rgba(201, 168, 106, 0.07), transparent 60%),
        radial-gradient(900px 500px at -10% 110%, rgba(176, 122, 74, 0.05), transparent 60%);
    background-attachment: fixed;
}

/* 全局极淡颗粒噪点，去除塑料感 */
body::after {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 9999;
    opacity: 0.035;
    mix-blend-mode: overlay;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

a { color: inherit; text-decoration: none; transition: color 0.3s var(--ease); }
img { max-width: 100%; display: block; }

.wrap {
    width: 100%;
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 0 28px;
}

em { font-style: normal; }

/* ---------- 标题排版（衬线） ---------- */
.hero-title, .section-title, .cta-title {
    font-family: var(--serif);
    font-weight: 500;
    line-height: 1.12;
    letter-spacing: 0.005em;
    color: var(--text);
    margin: 0;
}

/* ============================================================
   顶部导航
   ============================================================ */
.site-header {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    transition: background 0.4s var(--ease), border-color 0.4s var(--ease), backdrop-filter 0.4s var(--ease);
    border-bottom: 1px solid transparent;
}
.site-header.scrolled {
    background: rgba(20, 18, 15, 0.72);
    backdrop-filter: blur(14px) saturate(140%);
    -webkit-backdrop-filter: blur(14px) saturate(140%);
    border-bottom-color: var(--hair);
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 74px;
}
.brand {
    display: inline-flex;
    align-items: center;
    gap: 11px;
    color: var(--text);
}
.brand-mark { color: var(--gold); display: inline-flex; }
.brand-name {
    font-family: var(--serif);
    font-size: 20px;
    font-weight: 600;
    letter-spacing: 0.03em;
}
.nav {
    display: flex;
    gap: 38px;
    margin: 0 auto;
}
.nav a {
    color: var(--text-2);
    font-size: 14.5px;
    letter-spacing: 0.04em;
    position: relative;
    padding: 4px 0;
}
.nav a::after {
    content: "";
    position: absolute;
    left: 0; bottom: -2px;
    width: 0; height: 1px;
    background: var(--gold-grad);
    transition: width 0.35s var(--ease);
}
.nav a:hover { color: var(--text); }
.nav a:hover::after { width: 100%; }

.header-actions { display: flex; align-items: center; gap: 18px; }
.link-quiet { color: var(--text-2); font-size: 14.5px; letter-spacing: 0.04em; }
.link-quiet:hover { color: var(--gold-2); }

/* ---------- 按钮 ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: var(--sans);
    font-size: 15px;
    font-weight: 500;
    letter-spacing: 0.03em;
    padding: 14px 30px;
    border-radius: 100px;
    border: 1px solid transparent;
    cursor: pointer;
    transition: transform 0.3s var(--ease), box-shadow 0.4s var(--ease),
                background 0.3s var(--ease), color 0.3s var(--ease), border-color 0.3s var(--ease);
    white-space: nowrap;
}
.btn-sm { padding: 10px 22px; font-size: 14px; }

.btn-gold {
    background: var(--gold-grad);
    color: #211a0f;
    box-shadow: 0 6px 22px -8px rgba(201, 168, 106, 0.55);
}
.btn-gold:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 34px -10px rgba(201, 168, 106, 0.7);
    color: #1a140b;
}
.btn-ghost {
    background: transparent;
    color: var(--text);
    border-color: var(--hair);
}
.btn-ghost:hover { border-color: var(--hair-gold); color: var(--gold-2); transform: translateY(-2px); }
.btn-ghost .arr { transition: transform 0.3s var(--ease); }
.btn-ghost:hover .arr { transform: translateX(4px); }

.btn-outline {
    background: transparent;
    color: var(--gold-2);
    border-color: var(--hair-gold);
    margin-top: 30px;
}
.btn-outline:hover { background: rgba(201, 168, 106, 0.08); transform: translateY(-2px); }

/* 移动端汉堡 */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    width: 40px; height: 40px;
    background: none; border: none;
    cursor: pointer;
    padding: 10px 8px;
}
.nav-toggle span {
    display: block; height: 1.5px; width: 100%;
    background: var(--text);
    transition: transform 0.35s var(--ease), opacity 0.35s var(--ease);
}
.nav-toggle.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ============================================================
   英雄区
   ============================================================ */
.hero {
    position: relative;
    min-height: 100vh;
    min-height: 100svh;
    display: flex;
    align-items: center;
    padding: 120px 0 80px;
    overflow: hidden;
}
.hero-glow {
    position: absolute;
    top: -20%; left: 50%;
    transform: translateX(-50%);
    width: 1100px; height: 1100px;
    background: radial-gradient(circle, rgba(201, 168, 106, 0.14) 0%, rgba(176, 122, 74, 0.05) 38%, transparent 66%);
    pointer-events: none;
    filter: blur(10px);
}
.hero-inner { position: relative; text-align: center; }

.eyebrow {
    font-size: 13px;
    letter-spacing: 0.42em;
    text-transform: uppercase;
    color: var(--gold);
    margin: 0 0 26px;
    font-weight: 500;
}
.hero-title {
    font-size: clamp(42px, 8vw, 92px);
    margin-bottom: 30px;
}
.hero-title em {
    background: var(--gold-grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: var(--gold);
    font-style: italic;
}
.hero-sub {
    max-width: 620px;
    margin: 0 auto 42px;
    font-size: clamp(16px, 2vw, 19px);
    color: var(--text-2);
    line-height: 1.8;
}
.hero-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}
.hero-trust {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 18px;
    margin-top: 60px;
    color: var(--muted);
    font-size: 13px;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}
.hero-trust i { width: 4px; height: 4px; border-radius: 50%; background: var(--copper); opacity: 0.7; }

.scroll-cue {
    position: absolute;
    bottom: 34px; left: 50%;
    transform: translateX(-50%);
    width: 26px; height: 42px;
    border: 1px solid var(--hair-gold);
    border-radius: 14px;
    display: flex; justify-content: center;
}
.scroll-cue span {
    width: 3px; height: 8px;
    background: var(--gold);
    border-radius: 2px;
    margin-top: 8px;
    animation: scrollCue 1.8s var(--ease) infinite;
}
@keyframes scrollCue {
    0% { opacity: 0; transform: translateY(0); }
    35% { opacity: 1; }
    70% { opacity: 0; transform: translateY(12px); }
    100% { opacity: 0; }
}

/* ============================================================
   通用区块
   ============================================================ */
.section { position: relative; padding: 120px 0; }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 70px; }
.kicker {
    font-size: 12.5px;
    letter-spacing: 0.34em;
    text-transform: uppercase;
    color: var(--gold);
    margin: 0 0 18px;
    font-weight: 600;
}
.section-title { font-size: clamp(30px, 4.5vw, 50px); margin-bottom: 20px; }
.section-desc { color: var(--text-2); font-size: 17px; margin: 0; line-height: 1.8; }

.grid { display: grid; gap: 24px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* ---------- 功能卡片 ---------- */
.card {
    position: relative;
    background: linear-gradient(180deg, var(--bg-3), var(--bg-2));
    border: 1px solid var(--hair);
    border-radius: var(--radius);
    padding: 40px 34px;
    overflow: hidden;
    transition: transform 0.45s var(--ease), border-color 0.45s var(--ease), box-shadow 0.45s var(--ease);
}
.card::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--hair-gold), transparent);
    opacity: 0;
    transition: opacity 0.45s var(--ease);
}
.card:hover {
    transform: translateY(-6px);
    border-color: var(--hair-gold);
    box-shadow: 0 30px 60px -30px rgba(0, 0, 0, 0.7);
}
.card:hover::before { opacity: 1; }
.card-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 56px; height: 56px;
    border-radius: 14px;
    background: rgba(201, 168, 106, 0.1);
    border: 1px solid var(--hair-gold);
    color: var(--gold-2);
    margin-bottom: 24px;
}
.card h3 {
    font-family: var(--serif);
    font-size: 23px;
    font-weight: 600;
    margin: 0 0 12px;
    letter-spacing: 0.02em;
}
.card p { color: var(--muted); font-size: 15.5px; margin: 0; line-height: 1.75; }

/* ============================================================
   展示区
   ============================================================ */
.showcase { border-top: 1px solid var(--hair); }
.showcase-inner {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 70px;
    align-items: center;
}
.showcase-text .section-title { text-align: left; margin-bottom: 22px; }
.showcase-text .section-desc { margin-bottom: 28px; }
.check-list { list-style: none; padding: 0; margin: 0; }
.check-list li {
    position: relative;
    padding-left: 30px;
    margin-bottom: 14px;
    color: var(--text-2);
    font-size: 15.5px;
}
.check-list li::before {
    content: "";
    position: absolute;
    left: 0; top: 9px;
    width: 16px; height: 16px;
    border-radius: 50%;
    border: 1px solid var(--gold);
    background:
        linear-gradient(var(--gold), var(--gold)) no-repeat center/6px 1.5px,
        linear-gradient(var(--gold), var(--gold)) no-repeat center/1.5px 6px;
}

/* 抽象视觉框（替代实拍图，可后续换成真实图像） */
.showcase-visual { perspective: 1000px; }
.visual-frame {
    position: relative;
    aspect-ratio: 4 / 3.4;
    border-radius: 22px;
    background:
        radial-gradient(120% 90% at 30% 20%, rgba(201, 168, 106, 0.14), transparent 55%),
        linear-gradient(155deg, #26221c 0%, #16140f 100%);
    border: 1px solid var(--hair);
    overflow: hidden;
    box-shadow: 0 40px 80px -40px rgba(0, 0, 0, 0.8);
}
.visual-orb {
    position: absolute;
    top: 24%; left: 50%;
    transform: translateX(-50%);
    width: 46%; aspect-ratio: 1;
    border-radius: 50%;
    background: var(--gold-grad);
    filter: blur(2px);
    box-shadow: 0 0 80px -10px rgba(201, 168, 106, 0.6), inset 0 -20px 40px rgba(0,0,0,0.35);
    animation: float 7s var(--ease) infinite;
}
.visual-lines {
    position: absolute;
    inset: 0;
    background-image: repeating-linear-gradient(90deg, transparent, transparent 38px, rgba(243,237,225,0.04) 38px, rgba(243,237,225,0.04) 39px);
    mask-image: linear-gradient(180deg, transparent 55%, #000 100%);
    -webkit-mask-image: linear-gradient(180deg, transparent 55%, #000 100%);
}
.visual-chip {
    position: absolute;
    border-radius: 12px;
    background: rgba(31, 28, 24, 0.82);
    border: 1px solid var(--hair-gold);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
}
.chip-a { width: 38%; height: 54px; left: 8%; bottom: 16%; animation: float 6s var(--ease) infinite 0.4s; }
.chip-b { width: 26%; height: 44px; right: 9%; bottom: 30%; animation: float 8s var(--ease) infinite 1s; }
@keyframes float {
    0%, 100% { transform: translateY(0) translateX(0); }
    50% { transform: translateY(-12px); }
}

/* ============================================================
   数据区
   ============================================================ */
.metrics { border-top: 1px solid var(--hair); border-bottom: 1px solid var(--hair); padding: 90px 0; }
.metrics-grid { text-align: center; }
.metric { display: flex; flex-direction: column; gap: 10px; position: relative; }
.metric:not(:last-child)::after {
    content: "";
    position: absolute;
    right: -12px; top: 12%;
    height: 76%; width: 1px;
    background: var(--hair);
}
.metric-num {
    font-family: var(--serif);
    font-size: clamp(36px, 5vw, 56px);
    font-weight: 600;
    background: var(--gold-grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1;
}
.metric-label { color: var(--muted); font-size: 14px; letter-spacing: 0.1em; }

/* ============================================================
   行动召唤
   ============================================================ */
.cta-section { text-align: center; padding: 140px 0; overflow: hidden; }
.cta-glow {
    position: absolute;
    bottom: -40%; left: 50%;
    transform: translateX(-50%);
    width: 900px; height: 700px;
    background: radial-gradient(circle, rgba(201, 168, 106, 0.12), transparent 62%);
    pointer-events: none;
}
.cta-inner { position: relative; max-width: 720px; margin: 0 auto; }
.cta-title { font-size: clamp(32px, 5.5vw, 60px); margin-bottom: 18px; }
.cta-title em {
    background: var(--gold-grad);
    -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
    font-style: italic;
}
.cta-sub { color: var(--text-2); font-size: 18px; margin: 0 0 38px; }

/* ============================================================
   页脚
   ============================================================ */
.site-footer { border-top: 1px solid var(--hair); padding: 64px 0 30px; background: var(--bg-2); }
.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 40px;
    flex-wrap: wrap;
    padding-bottom: 40px;
    border-bottom: 1px solid var(--hair);
}
.footer-brand .brand-name { font-size: 22px; }
.footer-brand p { color: var(--muted); font-size: 14.5px; margin: 12px 0 0; max-width: 320px; }
.footer-nav { display: flex; gap: 30px; flex-wrap: wrap; }
.footer-nav a { color: var(--text-2); font-size: 14.5px; letter-spacing: 0.03em; }
.footer-nav a:hover { color: var(--gold-2); }
.footer-bottom { padding-top: 24px; }
.footer-bottom p { color: var(--faint); font-size: 13px; margin: 0; text-align: center; }
.footer-bottom a { color: var(--muted); }
.footer-bottom a:hover { color: var(--gold-2); }

/* ============================================================
   滚动入场动画
   ============================================================ */
.reveal {
    opacity: 0;
    transform: translateY(26px);
    transition: opacity 0.8s var(--ease), transform 0.8s var(--ease);
    transition-delay: calc(var(--d, 0) * 90ms);
}
.reveal.in { opacity: 1; transform: none; }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 980px) {
    .showcase-inner { grid-template-columns: 1fr; gap: 48px; }
    .showcase-text .section-title { text-align: center; }
    .showcase-text { text-align: center; }
    .check-list { display: inline-block; text-align: left; }
}

@media (max-width: 820px) {
    .nav, .link-quiet { display: none; }
    .nav-toggle { display: flex; }
    .nav.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 74px; left: 0; right: 0;
        margin: 0;
        gap: 0;
        background: rgba(20, 18, 15, 0.96);
        backdrop-filter: blur(14px);
        -webkit-backdrop-filter: blur(14px);
        border-bottom: 1px solid var(--hair);
        padding: 12px 28px 22px;
    }
    .nav.open a { padding: 14px 0; border-bottom: 1px solid var(--hair); font-size: 16px; }
    .grid-3 { grid-template-columns: 1fr; }
    .grid-4 { grid-template-columns: 1fr 1fr; }
    .metric:nth-child(2)::after { display: none; }
    .section { padding: 90px 0; }
}

@media (max-width: 520px) {
    .wrap { padding: 0 20px; }
    .grid-4 { grid-template-columns: 1fr 1fr; gap: 30px 16px; }
    .metric::after { display: none !important; }
    .hero-trust { gap: 12px; font-size: 11px; flex-wrap: wrap; }
    .btn { padding: 13px 26px; }
    .footer-inner { flex-direction: column; gap: 28px; }
}

/* 尊重用户的减弱动效偏好 */
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .reveal { opacity: 1; transform: none; transition: none; }
    .visual-orb, .visual-chip, .scroll-cue span { animation: none; }
    .btn, .card, .nav a::after { transition: none; }
}