/* Helium 浏览器中文下载站 — 原生 CSS，移动优先 */
:root {
  --bg: #f7f8fb;
  --surface: #ffffff;
  --text: #1c2333;
  --muted: #5b6472;
  --line: #e4e8ef;
  --accent: #2f48f0;
  --accent-dark: #2338c9;
  --teal: #0d9488;
  --warn-bg: #fff7e6;
  --warn-line: #f0d9a8;
  --radius: 14px;
  --max: 1080px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, sans-serif;
  background: var(--bg); color: var(--text);
  line-height: 1.7; font-size: 16px;
}
img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* 头部 */
.site-header { background: var(--surface); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 50; }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--text); font-size: 17px; }
.brand:hover { text-decoration: none; }
.brand .mark { width: 28px; height: 28px; border-radius: 7px; background: var(--accent); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 13px; font-weight: 800; letter-spacing: -.5px; }
.site-nav { display: flex; gap: 18px; font-size: 14px; }
.site-nav a { color: var(--muted); }

/* 首屏 */
.hero { padding: 56px 0 40px; text-align: center; background: linear-gradient(180deg, #eef1fb 0%, var(--bg) 100%); }
.hero h1 { font-size: clamp(26px, 5vw, 40px); letter-spacing: .5px; line-height: 1.3; }
.hero .wordmark { font-weight: 800; font-size: clamp(40px, 9vw, 72px); letter-spacing: -1px; color: var(--accent); line-height: 1.15; }
.hero .tagline { color: var(--muted); margin: 14px 0 6px; font-size: clamp(15px, 2.5vw, 18px); }
.hero .beta-tip { display: inline-block; font-size: 12.5px; color: #92600a; background: var(--warn-bg); border: 1px solid var(--warn-line); border-radius: 999px; padding: 3px 12px; margin-bottom: 18px; }
.btn-primary { display: inline-block; background: var(--accent); color: #fff; font-weight: 600; font-size: 17px; padding: 13px 34px; border-radius: 999px; border: none; cursor: pointer; box-shadow: 0 6px 18px rgba(47,72,240,.25); transition: transform .15s, background .15s; }
.btn-primary:hover { background: var(--accent-dark); text-decoration: none; transform: translateY(-1px); }
.hero .ver-note { margin-top: 12px; font-size: 13px; color: var(--muted); }

/* 区块 */
section { padding: 44px 0; }
section h2 { font-size: clamp(20px, 3.5vw, 26px); margin-bottom: 6px; }
.sec-sub { color: var(--muted); font-size: 14px; margin-bottom: 22px; }

/* 下载卡片 */
.dl-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 16px; }
.dl-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; display: flex; flex-direction: column; gap: 8px; }
.dl-card .os { font-size: 18px; font-weight: 700; display: flex; align-items: center; gap: 8px; }
.dl-card .os .ico { font-size: 22px; }
.dl-card .hint { color: var(--muted); font-size: 13.5px; }
.dl-card .meta { font-size: 12.5px; color: var(--muted); background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; word-break: break-all; }
.dl-card .meta b { color: var(--text); font-weight: 600; }
.dl-card .btn-primary { margin-top: 6px; text-align: center; font-size: 15.5px; padding: 11px 0; }
.dl-card .alt { font-size: 12.5px; color: var(--muted); }
.src-note { margin-top: 14px; font-size: 12.5px; color: var(--muted); }

/* 特色功能 */
.feat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.feat { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.feat .icon { font-size: 26px; }
.feat h3 { font-size: 16.5px; margin: 8px 0 4px; }
.feat p { font-size: 14px; color: var(--muted); }

/* 截图 */
.shot-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 16px; }
.shot { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.shot img { width: 100%; height: auto; aspect-ratio: 16 / 9; object-fit: cover; }
.shot figcaption { padding: 10px 14px; font-size: 13.5px; color: var(--muted); }

/* 系统要求 */
.req-table { width: 100%; border-collapse: collapse; background: var(--surface); border-radius: var(--radius); overflow: hidden; font-size: 14.5px; }
.req-table th, .req-table td { border: 1px solid var(--line); padding: 10px 14px; text-align: left; }
.req-table th { background: #eef1fb; font-weight: 600; }

/* Changelog */
.chlog { list-style: none; display: flex; flex-direction: column; gap: 12px; }
.chlog li { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px 18px; }
.chlog .v { font-weight: 700; margin-right: 10px; }
.chlog .d { font-size: 13px; color: var(--muted); }
.chlog p { font-size: 14px; color: var(--muted); margin-top: 6px; }

/* FAQ 首页精选 */
.faq-home details { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 0; margin-bottom: 10px; }
.faq-home summary { cursor: pointer; padding: 13px 16px; font-weight: 600; font-size: 15px; }
.faq-home details[open] summary { border-bottom: 1px solid var(--line); }
.faq-home .a { padding: 12px 16px; font-size: 14.5px; color: var(--muted); }
.more-link { display: inline-block; margin-top: 10px; font-size: 14.5px; }

/* 页脚 */
.site-footer { border-top: 1px solid var(--line); background: var(--surface); padding: 30px 0 40px; font-size: 13px; color: var(--muted); }
.site-footer .disclaim { background: var(--warn-bg); border: 1px solid var(--warn-line); color: #7a5b16; border-radius: 8px; padding: 10px 14px; margin-bottom: 14px; }
.site-footer p { margin: 4px 0; }
.footer-links { margin: 8px 0; }

/* 弹窗 */
.modal-mask { position: fixed; inset: 0; background: rgba(15,20,35,.55); display: none; align-items: center; justify-content: center; z-index: 100; padding: 16px; }
.modal-mask.open { display: flex; }
.modal { background: var(--surface); border-radius: 16px; max-width: 400px; width: 100%; max-height: 92vh; overflow-y: auto; padding: 24px; position: relative; text-align: center; }
.modal h3 { font-size: 17px; line-height: 1.45; margin-bottom: 14px; padding-right: 26px; }
.modal .close { position: absolute; top: 12px; right: 14px; border: none; background: none; font-size: 22px; color: var(--muted); cursor: pointer; line-height: 1; }
.modal img.qr { width: 220px; height: 220px; margin: 0 auto 12px; border: 1px solid var(--line); border-radius: 10px; padding: 6px; background: #fff; }
.modal .qr-tip { font-size: 14px; margin-bottom: 14px; }
.modal .btn-block { display: block; width: 100%; padding: 11px 0; border-radius: 10px; font-size: 15px; margin-bottom: 9px; cursor: pointer; border: none; font-weight: 600; }
.modal .btn-quark { background: var(--accent); color: #fff; }
.modal .btn-quark:hover { background: var(--accent-dark); }
.modal .btn-copy { background: #eef1fb; color: var(--accent); border: 1px solid #d8defc !important; }
.modal .meta { font-size: 12px; color: var(--muted); text-align: left; background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; word-break: break-all; margin-top: 6px; }
.modal .meta b { color: var(--text); }
.modal .qr-missing { font-size: 14px; color: #92600a; background: var(--warn-bg); border: 1px solid var(--warn-line); border-radius: 8px; padding: 12px; margin-bottom: 12px; }

/* 内页 */
.page-head { padding: 40px 0 8px; }
.page-head h1 { font-size: clamp(24px, 4.5vw, 32px); }
.article { max-width: 780px; margin: 0 auto; }
.article h2 { font-size: 21px; margin: 34px 0 12px; }
.article h3 { font-size: 17px; margin: 24px 0 10px; }
.article p, .article li { font-size: 15.5px; color: #333c4d; margin-bottom: 10px; }
.article ul, .article ol { padding-left: 24px; margin-bottom: 12px; }
.article .shot { margin: 16px 0; }
.article code { background: #eef1fb; border-radius: 5px; padding: 2px 7px; font-size: 13.5px; }
.article .tip { background: var(--warn-bg); border: 1px solid var(--warn-line); border-radius: 8px; padding: 10px 14px; font-size: 14px; margin: 14px 0; }
.faq-list details { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; margin-bottom: 10px; }
.faq-list summary { cursor: pointer; padding: 13px 16px; font-weight: 600; font-size: 15px; }
.faq-list details[open] summary { border-bottom: 1px solid var(--line); }
.faq-list .a { padding: 12px 16px; font-size: 14.5px; color: #454e5f; }

/* 配置加载失败提示 */
.config-error { background: #fdeaea; border: 1px solid #f2b8b8; color: #9c2020; border-radius: 10px; padding: 14px 18px; margin: 20px auto; max-width: 720px; font-size: 14px; }

@media (max-width: 640px) {
  .site-nav { gap: 12px; font-size: 13px; }
  section { padding: 32px 0; }
}