/* ============================================================
   Tiiiair 品牌官网 — 全局样式
   风格：白色背景为主，白/浅灰交替区块，科技绿强调
   字体：DouyinSansBold(标题) + HarmonyOS Sans SC(正文)
   ============================================================ */

@font-face {
    font-family: "Tiiiair Douyin";
    src: url("../fonts/DouyinSansBold.otf") format("opentype");
    font-weight: 700 900; font-style: normal; font-display: swap;
}
@font-face {
    font-family: "Tiiiair Sans";
    src: url("../fonts/HarmonyOS_Sans_SC_Regular.ttf") format("truetype");
    font-weight: 400; font-style: normal; font-display: swap;
}

/* ---------- 设计令牌 ---------- */
:root {
    /* 颜色 —— 白底配色 */
    --c-bg:        #ffffff;     /* 主背景 白 */
    --c-bg-alt:    #f5f6f8;     /* 次背景 浅灰（交替区块） */
    --c-bg-card:   #ffffff;     /* 卡片底 白 */
    --c-text:      #1a1d22;     /* 主文字 深黑 */
    --c-text-mute: #8a8f96;     /* 次文字 中灰 */
    --c-text-soft: #555b63;     /* 软文字 深灰 */
    --c-accent:    #2d7d6e;     /* 强调色 科技绿 */
    --c-accent-2:  #2d7d6e;     /* 次强调 */
    --c-line:      #e4e7eb;     /* 分割线 浅灰 */
    --c-white:     #ffffff;
    --c-dark:      #1a1d22;     /* 深色（Hero/Footer用） */

    /* 字体 */
    --font-head: "Tiiiair Douyin", "HarmonyOS Sans SC", "PingFang SC", sans-serif;
    --font-body: "Tiiiair Sans", "HarmonyOS Sans SC", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;

    /* 尺寸 */
    --maxw: 1440px;
    --pad-x: clamp(20px, 4vw, 80px);
    --radius: 14px;
    --radius-lg: 24px;
    --shadow: 0 12px 40px rgba(0,0,0,.08);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
    padding-top: 80px;
    margin: 0;
    background: var(--c-bg);
    color: var(--c-text);
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; transition: color .2s; }
a:hover { color: var(--c-accent-2); }
img { display: block; max-width: 100%; height: auto; }
h1, h2, h3, h4, h5, h6 {
    margin: 0;
    font-family: var(--font-head);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -.01em;
}
p { margin: 0 0 1em; }
ul, ol { margin: 0; padding: 0; list-style: none; }
button { font-family: inherit; cursor: pointer; }

/* ---------- 通用容器 ---------- */
.container {
    width: 100%;
    max-width: var(--maxw);
    margin-inline: auto;
    padding-inline: var(--pad-x);
}

/* ---------- 页面内页 Banner ---------- */
.page-banner {
    position: relative;
    min-height: 440px;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, rgba(10,10,10,.7), rgba(10,10,10,.5)),
                var(--page-banner-img, none) center/cover no-repeat;
    background-color: var(--c-bg-alt);
    border-bottom: 1px solid var(--c-line);
}
.page-banner .container { position: relative; z-index: 2; }
.page-banner h1 {
    font-size: clamp(32px, 4vw, 54px);
    color: var(--c-white);
}
.page-banner .breadcrumb {
    margin-bottom: 12px;
    font-size: 14px;
    color: var(--c-text-mute);
    letter-spacing: .05em;
}
.page-banner .breadcrumb a:hover { color: var(--c-accent-2); }
.page-banner .lead {
    margin-top: 16px;
    max-width: 680px;
    color: rgba(255,255,255,.65);
    font-size: clamp(15px, 1.3vw, 18px);
    text-shadow: 0 2px 8px rgba(0,0,0,.3);
}

/* ---------- 章节通用 ---------- */
.section { padding: clamp(40px, 4vw, 64px) 0; }
.section--alt { background: var(--c-bg-alt); }
.section--tight { padding: clamp(24px, 2.5vw, 36px) 0; }

.section-head { margin-bottom: clamp(20px, 2.5vw, 32px); }
.section-head--center { text-align: center; }
.section-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    color: var(--c-accent-2);
    font-family: var(--font-head);
    font-size: 13px;
    letter-spacing: .18em;
    text-transform: uppercase;
}
.section-eyebrow::before {
    content: "";
    width: 28px; height: 2px;
    background: var(--c-accent);
}
.section-head h2 {
    font-size: clamp(28px, 3.6vw, 48px);
}
.section-head p {
    margin-top: 16px;
    max-width: 640px;
    color: var(--c-text-soft);
    font-size: clamp(15px, 1.2vw, 17px);
}
.section-head--center p { margin-inline: auto; }

/* ---------- 按钮 ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    height: 50px;
    padding: 0 28px;
    border: 1px solid transparent;
    border-radius: 999px;
    font-family: var(--font-head);
    font-size: 15px;
    font-weight: 700;
    line-height: 1;
    transition: all .25s;
    white-space: nowrap;
}
.btn--solid {
    background: var(--c-accent);
    border-color: var(--c-accent);
    color: var(--c-white);
}
.btn--solid:hover { background: var(--c-accent-2); border-color: var(--c-accent-2); color: var(--c-white); transform: translateY(-2px); }
.btn--outline {
    border-color: var(--c-line);
    color: var(--c-text);
    background: transparent;
}
.btn--outline:hover { border-color: var(--c-accent); color: var(--c-accent-2); }
.btn--ghost {
    border-color: var(--c-line);
    color: var(--c-text);
    background: rgba(255,255,255,.15);
    backdrop-filter: blur(4px);
}
.btn--ghost:hover { border-color: var(--c-white); color: var(--c-white); }
.btn--sm { height: 40px; padding: 0 20px; font-size: 13px; }
.btn--lg { height: 56px; padding: 0 34px; font-size: 16px; }

/* ---------- 数据统计 ---------- */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}
.stat-item {
    padding: clamp(20px, 2vw, 28px) 20px;
    background: var(--c-bg-card);
    border: 1px solid var(--c-line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: border-color .25s, transform .25s;
}
.stat-item:hover { border-color: var(--c-accent); transform: translateY(-4px); }
.stat-num {
    font-family: var(--font-head);
    font-size: clamp(28px, 3vw, 44px);
    font-weight: 900;
    color: var(--c-accent-2);
    line-height: 1;
}
.stat-label {
    margin-top: 8px;
    color: var(--c-text-mute);
    font-size: 14px;
}

/* ---------- 卡片 ---------- */
.card {
    padding: clamp(20px, 2vw, 28px);
    background: var(--c-bg-card);
    border: 1px solid var(--c-line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: border-color .25s, transform .25s;
    height: 100%;
}
.card:hover { border-color: rgba(45,125,110,.5); transform: translateY(-3px); }
.card-icon {
    width: 44px; height: 44px;
    object-fit: contain;
    margin-bottom: 14px;
}
.card h3 {
    font-size: 20px;
    margin-bottom: 10px;
}
.card p { color: var(--c-text-soft); font-size: 15px; margin: 0; }
.card-num {
    font-family: var(--font-head);
    font-size: clamp(24px, 2.2vw, 34px);
    color: var(--c-accent-2);
    display: block;
    margin-bottom: 14px;
}

/* ---------- 表格 ---------- */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--c-line); }
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 15px;
}
th, td {
    padding: 16px 20px;
    text-align: left;
    border-bottom: 1px solid var(--c-line);
}
th {
    background: var(--c-bg-card);
    color: var(--c-text);
    font-family: var(--font-head);
    font-weight: 700;
    white-space: nowrap;
}
td { color: var(--c-text-soft); }
tbody tr:last-child td { border-bottom: 0; }
tbody tr:hover { background: rgba(45,125,110,.06); }

/* ============================================================
   导航栏 Header
   ============================================================ */
.site-header {
    position: fixed;
    inset: 0 0 auto 0;
    z-index: 100;
    height: 80px;
    background: rgba(15,17,20,.92);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255,255,255,.08);
    transition: height .3s, background .3s;
}
.site-header.is-scrolled {
    height: 64px;
    background: rgba(15,17,20,.98);
}
.header-inner {
    width: 100%;
    max-width: var(--maxw);
    height: 100%;
    margin-inline: auto;
    padding-inline: var(--pad-x);
    display: flex;
    align-items: center;
    gap: 32px;
}
.site-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-head);
    font-weight: 900;
    font-size: 24px;
    color: #fff;
    flex-shrink: 0;
}
.site-logo img { max-height: 36px; width: auto; }
.site-logo .logo-text { letter-spacing: .02em; }

.main-nav {
    margin-left: auto;
    display: flex;
    align-items: center;
}
.main-nav ul {
    display: flex;
    align-items: center;
    gap: clamp(16px, 1.8vw, 30px);
}
.main-nav a {
    display: block;
    padding: 8px 0;
    color: rgba(255,255,255,.75);
    font-size: 15px;
    font-weight: 500;
    position: relative;
}
.main-nav a:hover, .main-nav li.active a { color: #fff; }
.main-nav a::after {
    content: "";
    position: absolute;
    left: 0; bottom: 0;
    width: 0; height: 2px;
    background: #fff;
    transition: width .25s;
}
.main-nav a:hover::after, .main-nav li.active a::after { width: 100%; }

/* 下拉菜单 */
.main-nav .has-dropdown { position: relative; }
.main-nav .has-dropdown > a::before {
    content: "";
    position: absolute;
    left: 0; right: 0; bottom: -16px;
    height: 16px;
}
.main-nav .dropdown {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(10px);
    min-width: 220px;
    padding: 12px;
    background: rgba(15,17,20,.98);
    border: 1px solid rgba(255,255,255,.1);
    border-radius: var(--radius);
    box-shadow: 0 20px 50px rgba(0,0,0,.4);
    backdrop-filter: blur(12px);
    opacity: 0;
    visibility: hidden;
    transition: opacity .25s, transform .25s, visibility .25s;
    z-index: 110;
}
.main-nav .has-dropdown:hover .dropdown,
.main-nav .has-dropdown:focus-within .dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}
.main-nav .dropdown li { width: 100%; }
.main-nav .dropdown li a {
    display: block;
    padding: 12px 16px;
    color: rgba(255,255,255,.75);
    font-size: 14px;
    border-radius: 8px;
    transition: background .2s, color .2s;
}
.main-nav .dropdown li a::after { display: none; }
.main-nav .dropdown li a:hover {
    background: rgba(255,255,255,.08);
    color: #fff;
}

.header-cta { margin-left: 16px; }

.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 42px; height: 42px;
    margin-left: auto;
    border: 1px solid rgba(255,255,255,.25);
    border-radius: 50%;
    background: transparent;
}
.nav-toggle span {
    width: 18px; height: 2px;
    margin-inline: auto;
    background: #fff;
    border-radius: 2px;
    transition: all .3s;
}

/* ============================================================
   Footer（深色底，与白色页面形成对比）
   ============================================================ */
.site-footer {
    background: #1a1d22;
    color: #b8bdc4;
    padding: clamp(50px, 5vw, 80px) 0 30px;
}
.footer-top {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,.1);
}
.footer-brand .site-logo { margin-bottom: 20px; color: #fff; }
.footer-brand p {
    color: #8a8f96;
    font-size: 15px;
    max-width: 320px;
}
.footer-slogan {
    margin-top: 20px;
    font-family: var(--font-head);
    font-size: 22px;
    color: #fff;
}
.footer-col h4 {
    font-size: 16px;
    margin-bottom: 18px;
    color: #fff;
}
.footer-col ul li { margin-bottom: 10px; }
.footer-col a {
    color: var(--c-text-mute);
    font-size: 14px;
}
.footer-col a:hover { color: var(--c-accent-2); }

.footer-contact li {
    display: flex;
    gap: 10px;
    margin-bottom: 12px;
    color: var(--c-text-mute);
    font-size: 14px;
}
.footer-contact li strong { color: var(--c-text-soft); min-width: 50px; display: inline-block; }

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    padding-top: 24px;
    color: var(--c-text-mute);
    font-size: 13px;
}
.footer-bottom a { color: var(--c-text-mute); }
.footer-bottom a:hover { color: var(--c-accent-2); }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1080px) {
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-top { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 900px) {
    .site-header { height: 64px; }
    .header-inner { gap: 16px; }
    .nav-toggle { display: flex; }
    .main-nav {
        position: fixed;
        inset: 58px 14px auto;
        display: none;
        flex-direction: column;
        align-items: stretch;
        padding: 20px;
        background: rgba(15,17,20,.98);
        border: 1px solid rgba(255,255,255,.1);
        border-radius: var(--radius);
        backdrop-filter: blur(20px);
    }
    .main-nav.is-open { display: flex; }
    .main-nav ul { flex-direction: column; gap: 4px; }
    .main-nav a { padding: 12px 0; font-size: 16px; border-bottom: 1px solid var(--c-line); }
    .main-nav a::after { display: none; }
    .header-cta { margin: 8px 0 0; }
    .header-cta .btn { width: 100%; }
}
@media (max-width: 640px) {
    :root { --pad-x: 20px; }
    .stats-grid { grid-template-columns: 1fr; }
    .footer-top { grid-template-columns: 1fr; gap: 28px; }
    .footer-bottom { flex-direction: column; text-align: center; }
    .page-banner { min-height: 360px; }
}

/* ============================================================
   品牌记忆图标 (跟随文字高度)
   用法: <img class="brand-mark" src="...ico.png" alt="">
   ============================================================ */
.brand-mark {
    display: inline-block !important;
    height: 1em !important;
    width: auto !important;
    max-width: none !important;
    margin-left: 0.3em;
    vertical-align: -0.15em;
    opacity: .92;
    pointer-events: none;
    user-select: none;
    object-fit: contain;
}
/* 白底场景(浅色文字)图标用反白 */
.brand-mark--light { filter: brightness(0) invert(1); }
/* 按钮内图标对齐微调 */
/* flex 按钮内图标: 不破坏 flex 流, 跟随文字居中 */
.btn .brand-mark,
a .brand-mark {
    flex: 0 0 auto;
    align-self: center;
    margin-left: 0.3em;
    margin-top: 0;
    vertical-align: baseline;
    position: relative;
    top: 0;
}
/* 非按钮的纯 a 链接(如手风琴CTA/查看详情)内图标对齐 */
a:not(.btn) .brand-mark {
    vertical-align: -0.15em;
}