/* 河流日记官网 — "证据台"设计语言
   暖纸底 + 发丝线 + 钢蓝单强调色;无渐变、无装饰色块。 */

:root {
  --canvas: #f6f3ee;
  --surface: #fffefb;
  --well: #f1ede6;
  --border: #e6dfd2;
  --border-strong: #d8cfbf;
  --ink: #1f242b;
  --ink2: #4d5563;
  --ink3: #8a92a0;
  --accent: #43698c;
  --accent-strong: #33506e;
  --accent-soft: #e8eef4;
  --accent-border: #c9d8e6;
  --ok: #3f7d5b;
  --ok-soft: #e7f2ec;
  --warn: #a86b2d;
  --warn-soft: #f7efe2;
  --bad: #a84a4a;
  --bad-soft: #f7e9e9;
  --radius: 10px;
  --radius-sm: 6px;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Noto Sans CJK SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", Georgia, serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--ink);
  background: var(--canvas);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-strong); text-decoration: underline; text-underline-offset: 3px; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

/* ---------- 顶部导航 ---------- */
.topbar {
  border-bottom: 1px solid var(--border);
  background: rgba(246, 243, 238, 0.92);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 50;
}
.topbar-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 60px; gap: 16px;
}
.wordmark {
  display: flex; align-items: baseline; gap: 10px;
  color: var(--ink); font-weight: 600; font-size: 17px;
}
.wordmark:hover { text-decoration: none; }
.wordmark .en {
  font-family: var(--mono); font-size: 11px; letter-spacing: 0.12em;
  color: var(--ink3); text-transform: uppercase;
}
.topnav { display: flex; align-items: center; gap: 22px; font-size: 14px; }
.topnav a { color: var(--ink2); }
.topnav a:hover { color: var(--ink); text-decoration: none; }
.btn {
  display: inline-block; padding: 8px 18px;
  border: 1px solid var(--accent); border-radius: var(--radius-sm);
  color: var(--surface); background: var(--accent);
  font-size: 14px; font-weight: 500; line-height: 1.5;
  transition: background 0.15s ease, border-color 0.15s ease;
}
.btn:hover { background: var(--accent-strong); border-color: var(--accent-strong); color: var(--surface); text-decoration: none; }
.btn.ghost { background: transparent; color: var(--accent); }
.btn.ghost:hover { background: var(--accent-soft); color: var(--accent-strong); }
.btn.big { padding: 11px 26px; font-size: 15px; }

/* ---------- Hero ---------- */
.hero { padding: 84px 0 64px; border-bottom: 1px solid var(--border); }
.hero-grid { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 56px; align-items: center; }
.kicker {
  font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--accent);
  display: inline-flex; align-items: center; gap: 10px;
}
.kicker::before { content: ""; width: 26px; height: 1px; background: var(--accent); }
h1.hero-title {
  font-family: var(--serif); font-size: 44px; line-height: 1.28;
  font-weight: 600; letter-spacing: 0.01em; margin: 18px 0 20px;
}
.hero-sub { color: var(--ink2); font-size: 16.5px; max-width: 34em; }
.hero-ctas { display: flex; gap: 14px; margin-top: 30px; flex-wrap: wrap; }
.hero-chips { display: flex; gap: 10px; margin-top: 26px; flex-wrap: wrap; }
.chip {
  font-size: 12.5px; padding: 4px 12px; border-radius: 999px;
  border: 1px solid var(--border-strong); background: var(--surface); color: var(--ink2);
}
.hero-panel {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 26px 24px 18px;
  box-shadow: 0 1px 2px rgba(31, 36, 43, 0.04);
}
.hero-panel .panel-head {
  display: flex; justify-content: space-between; align-items: baseline;
  padding-bottom: 12px; border-bottom: 1px solid var(--border);
}
.hero-panel .panel-date { font-family: var(--serif); font-size: 17px; font-weight: 600; }
.hero-panel .panel-tag { font-family: var(--mono); font-size: 10.5px; color: var(--ink3); letter-spacing: 0.1em; }
.hero-svg { display: block; width: 100%; height: auto; margin-top: 10px; }
.hero-note {
  margin-top: 12px; font-size: 12.5px; color: var(--ink3);
  display: flex; justify-content: space-between; align-items: center;
}

/* 状态徽标:颜色永远是第二通道,文字承载含义 */
.tag {
  display: inline-block; font-size: 11.5px; padding: 2px 9px;
  border-radius: 4px; border: 1px solid; line-height: 1.6;
}
.tag.fact { color: var(--ok); background: var(--ok-soft); border-color: #cde3d6; }
.tag.infer { color: var(--warn); background: var(--warn-soft); border-color: #ecdcc6; }
.tag.partial { color: var(--accent); background: var(--accent-soft); border-color: var(--accent-border); }
.tag.fixable { color: var(--ink2); background: var(--well); border-color: var(--border-strong); }

/* ---------- 通用 section ---------- */
section.band { padding: 72px 0; border-bottom: 1px solid var(--border); }
section.band:last-of-type { border-bottom: none; }
.section-head { margin-bottom: 40px; max-width: 40em; }
.section-head h2 {
  font-family: var(--serif); font-size: 30px; font-weight: 600;
  margin: 12px 0 10px; letter-spacing: 0.01em;
}
.section-head p { color: var(--ink2); font-size: 15.5px; }

.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }

.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 26px 24px;
}
.card h3 { font-size: 16.5px; font-weight: 600; margin-bottom: 10px; }
.card h3 .no {
  font-family: var(--mono); font-size: 11px; color: var(--ink3);
  margin-right: 10px; font-weight: 400;
}
.card p { color: var(--ink2); font-size: 14px; line-height: 1.8; }
.card .demo { margin-top: 14px; display: flex; gap: 8px; flex-wrap: wrap; }

/* 理念条 */
.belief {
  font-family: var(--serif); font-size: 22px; line-height: 1.7;
  max-width: 30em; color: var(--ink);
}
.belief em { font-style: normal; color: var(--accent); }
.principles { margin-top: 36px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); overflow: hidden; }
.principle { padding: 22px 20px; border-right: 1px solid var(--border); }
.principle:last-child { border-right: none; }
.principle b { display: block; font-size: 14.5px; margin-bottom: 6px; }
.principle span { font-size: 13px; color: var(--ink2); line-height: 1.7; }

/* 云服务 */
.cloud-grid { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 20px; align-items: stretch; }
.cloud-list { list-style: none; }
.cloud-list li { padding: 13px 0; border-bottom: 1px solid var(--border); font-size: 14.5px; color: var(--ink2); display: flex; gap: 12px; }
.cloud-list li:last-child { border-bottom: none; }
.cloud-list li b { color: var(--ink); font-weight: 600; min-width: 7.5em; }
.boundary { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.boundary .col { padding: 22px 24px; }
.boundary .col + .col { border-top: 1px solid var(--border); }
.boundary h4 { font-size: 13.5px; margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }
.boundary ul { list-style: none; }
.boundary li { font-size: 13.5px; color: var(--ink2); padding: 4px 0 4px 20px; position: relative; }
.boundary li::before { content: ""; position: absolute; left: 4px; top: 13px; width: 7px; height: 1px; background: var(--ink3); }
.boundary .yes h4 { color: var(--ok); }
.boundary .no h4 { color: var(--bad); }
.cloud-note {
  margin-top: 18px; font-size: 12.5px; color: var(--ink3);
  border-left: 2px solid var(--accent-border); padding: 2px 0 2px 14px; line-height: 1.8;
}
.cloud-actions { margin-top: 26px; display: flex; gap: 14px; flex-wrap: wrap; }

/* 下载 */
.dl-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.dl-card { display: flex; flex-direction: column; gap: 12px; }
.dl-card .platform { font-family: var(--mono); font-size: 11px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink3); }
.dl-card h3 { font-size: 17px; font-weight: 600; }
.dl-card p { font-size: 13.5px; color: var(--ink2); }
.dl-actions { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; margin-top: auto; }
.dl-meta { font-family: var(--mono); font-size: 11px; color: var(--ink3); word-break: break-all; }
.soon { display: inline-block; font-size: 12px; color: var(--ink3); border: 1px dashed var(--border-strong); border-radius: 999px; padding: 3px 12px; }

/* FAQ */
.faq { max-width: 46em; }
.faq details { border-bottom: 1px solid var(--border); padding: 16px 4px; }
.faq details:first-child { border-top: 1px solid var(--border); }
.faq summary { cursor: pointer; font-weight: 600; font-size: 15px; list-style: none; display: flex; justify-content: space-between; align-items: center; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font-family: var(--mono); color: var(--ink3); font-size: 17px; }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin-top: 10px; color: var(--ink2); font-size: 14px; line-height: 1.85; }

/* 页脚 */
footer.site { padding: 44px 0 60px; color: var(--ink3); font-size: 13px; }
.foot-grid { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; align-items: flex-start; }
.foot-links { display: flex; gap: 18px; flex-wrap: wrap; }
.foot-links a { color: var(--ink2); }
.foot-note { margin-top: 14px; font-size: 12px; line-height: 1.8; max-width: 46em; }

/* ---------- 文档页(条款/隐私) ---------- */
.doc { max-width: 760px; margin: 0 auto; padding: 56px 24px 80px; }
.doc .doc-head { border-bottom: 1px solid var(--border); padding-bottom: 22px; margin-bottom: 34px; }
.doc .doc-ver { font-family: var(--mono); font-size: 11.5px; color: var(--ink3); letter-spacing: 0.1em; }
.doc h1 { font-family: var(--serif); font-size: 32px; font-weight: 600; margin-top: 10px; }
.doc h2 { font-size: 17px; font-weight: 600; margin: 34px 0 10px; }
.doc p, .doc li { color: var(--ink2); font-size: 14.5px; line-height: 1.9; }
.doc ul { padding-left: 22px; margin: 8px 0; }
.doc strong { color: var(--ink); font-weight: 600; }
.doc .callout {
  border: 1px solid var(--accent-border); background: var(--accent-soft);
  border-radius: var(--radius-sm); padding: 14px 18px; margin: 16px 0;
  font-size: 13.5px; color: var(--accent-strong);
}
.doc .backline { margin-bottom: 30px; font-size: 13px; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .hero-grid, .grid-3, .grid-2, .cloud-grid, .dl-grid { grid-template-columns: 1fr; }
  .principles { grid-template-columns: 1fr 1fr; }
  .principle:nth-child(2) { border-right: none; }
  .principle:nth-child(-n+2) { border-bottom: 1px solid var(--border); }
  h1.hero-title { font-size: 34px; }
  .topnav .hide-m { display: none; }
}