/* 良辰数学官网 · 黑白极简风格
   规则：白底黑字，唯一的强调色是纯黑本身；
   层次靠字重、字号与 1px 细线，不靠色彩。 */

:root {
  --ink: #111111;
  --bg: #ffffff;
  --muted: #6f6f6f;
  --line: #e4e4e4;
  --soft: #fafafa;
  --mono: ui-monospace, "SFMono-Regular", Consolas, "Courier New", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --max: 1080px;
}

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

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

body {
  font-family: var(--sans);
  color: var(--ink);
  background: var(--bg);
  font-size: 16px;
  line-height: 1.7;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------------- 顶栏 ---------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.06em;
}

.brand-mark {
  width: 40px;
  height: 40px;
  display: block;
  border-radius: 9px;
  object-fit: contain;
  background: #fff;
  /* 图标本身是白底线条，加一圈极淡描边避免与白色顶栏糊在一起 */
  box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.07);
}

.site-nav {
  display: flex;
  gap: 28px;
  font-size: 15px;
}

.site-nav a {
  color: var(--muted);
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.site-nav a:hover { color: var(--ink); border-bottom-color: var(--ink); }
.site-nav a.active { color: var(--ink); border-bottom-color: var(--ink); }

/* ---------------- 按钮 ---------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  font-size: 15px;
  font-family: var(--sans);
  border-radius: 3px;
  border: 1px solid var(--ink);
  cursor: pointer;
  transition: background 0.15s, color 0.15s, opacity 0.15s;
  white-space: nowrap;
}

.btn-primary { background: var(--ink); color: #fff; }
.btn-primary:hover { opacity: 0.82; }

.btn-ghost { background: transparent; color: var(--ink); }
.btn-ghost:hover { background: var(--ink); color: #fff; }

.btn-lg { padding: 16px 40px; font-size: 17px; }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn[disabled] { opacity: 0.4; cursor: not-allowed; }

/* ---------------- 首页 Hero ---------------- */

.hero {
  padding: 96px 0 80px;
  border-bottom: 1px solid var(--line);
}

.hero-kicker {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.35em;
  color: var(--muted);
  text-transform: uppercase;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 56px;
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: 0.02em;
  margin-bottom: 24px;
}

.hero p.lead {
  font-size: 19px;
  color: var(--muted);
  max-width: 560px;
  margin-bottom: 40px;
}

.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 28px; }

.hero-meta {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--muted);
}

.hero-meta strong { color: var(--ink); font-weight: 600; }

/* ---------------- 数据条 ---------------- */

.stats {
  border-bottom: 1px solid var(--line);
  background: var(--soft);
}

.stats .container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  padding-top: 32px;
  padding-bottom: 32px;
}

.stat { text-align: center; }
.stat b { display: block; font-size: 34px; font-weight: 800; line-height: 1.2; }
.stat span { font-size: 14px; color: var(--muted); letter-spacing: 0.12em; }

/* ---------------- 功能区 ---------------- */

.section { padding: 88px 0; }
.section + .section { border-top: 1px solid var(--line); }

.section-head { margin-bottom: 48px; }
.section-head .kicker {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.3em;
  color: var(--muted);
  margin-bottom: 12px;
}
.section-head h2 { font-size: 32px; font-weight: 800; letter-spacing: 0.02em; }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.feature {
  background: var(--bg);
  padding: 32px 28px;
  transition: background 0.15s;
}
.feature:hover { background: var(--soft); }

.feature .no {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.2em;
}
.feature h3 { font-size: 19px; font-weight: 700; margin: 14px 0 10px; }
.feature p { font-size: 14.5px; color: var(--muted); }

/* ---------------- 下载页 ---------------- */

.page-title { padding: 64px 0 40px; border-bottom: 1px solid var(--line); }
.page-title h1 { font-size: 40px; font-weight: 800; margin-top: 8px; }
.page-title p { color: var(--muted); margin-top: 8px; }

.release-hero {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  padding: 56px 24px;
  border-bottom: 1px solid var(--line);
}

.release-hero .version-no {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: 0.25em;
  color: var(--muted);
}
.release-hero .version {
  font-size: 52px;
  font-weight: 800;
  line-height: 1.15;
  margin: 8px 0 20px;
}
.release-hero .tagline { color: var(--muted); margin-bottom: 32px; }

.release-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.release-actions .direct {
  font-size: 13px;
  color: var(--muted);
  align-self: center;
  border-bottom: 1px solid var(--line);
}
.release-actions .direct:hover { color: var(--ink); border-bottom-color: var(--ink); }

.meta-card { border: 1px solid var(--line); }
.meta-card .row {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 20px;
  font-size: 14px;
  border-bottom: 1px solid var(--line);
}
.meta-card .row:last-child { border-bottom: none; }
.meta-card .k { color: var(--muted); flex-shrink: 0; }
.meta-card .v { font-family: var(--mono); font-size: 13px; text-align: right; word-break: break-all; }

.notes-block { padding: 48px 24px; border-bottom: 1px solid var(--line); }
.notes-block h2 { font-size: 20px; font-weight: 700; margin-bottom: 16px; }
.notes-block pre {
  font-family: var(--sans);
  white-space: pre-wrap;
  word-break: break-word;
  color: #333;
  font-size: 15px;
}
.notes-block .empty { color: var(--muted); font-size: 14px; }

.release-list { padding: 48px 24px 88px; }
.release-list h2 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.release-list .sub { color: var(--muted); font-size: 14px; margin-bottom: 24px; }

.release-item { border: 1px solid var(--line); border-bottom: none; }
.release-item:last-child { border-bottom: 1px solid var(--line); }

.release-item .head {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 20px;
  cursor: pointer;
  user-select: none;
}
.release-item .head:hover { background: var(--soft); }
.release-item .v { font-weight: 700; min-width: 90px; }
.release-item .m {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--muted);
  flex: 1;
}
.release-item .caret { color: var(--muted); font-size: 12px; transition: transform 0.15s; }
.release-item.open .caret { transform: rotate(90deg); }

.release-item .body { display: none; padding: 0 20px 20px; }
.release-item.open .body { display: block; }
.release-item .body pre {
  font-family: var(--sans);
  white-space: pre-wrap;
  word-break: break-word;
  color: #333;
  font-size: 14px;
  margin-bottom: 14px;
  border-left: 2px solid var(--ink);
  padding-left: 14px;
}
.release-item .body .ops { display: flex; gap: 12px; align-items: center; }
.release-item .body .sha {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--muted);
  word-break: break-all;
  flex: 1;
}

.empty-state {
  padding: 64px 0 96px;
  text-align: center;
  color: var(--muted);
}
.empty-state b { display: block; color: var(--ink); font-size: 20px; margin-bottom: 8px; }

.install-note { padding: 48px 24px 88px; border-top: 1px solid var(--line); }
.install-note h2 { font-size: 20px; font-weight: 700; margin-bottom: 16px; }
.install-note ol { padding-left: 22px; color: #333; font-size: 15px; }
.install-note li { margin-bottom: 8px; }

/* ---------------- 后台 ---------------- */

.admin-wrap { max-width: 720px; margin: 0 auto; padding: 56px 24px 96px; }
.admin-section { margin-bottom: 48px; }
.admin-section > h2 { font-size: 20px; font-weight: 700; margin-bottom: 20px; }

.card { border: 1px solid var(--line); padding: 28px; }

.field { margin-bottom: 20px; }
.field label {
  display: block;
  font-size: 13.5px;
  color: var(--muted);
  margin-bottom: 8px;
  letter-spacing: 0.04em;
}
.field input[type="text"],
.field input[type="password"],
.field input[type="number"],
.field textarea,
.field input[type="file"] {
  width: 100%;
  padding: 10px 12px;
  font-size: 15px;
  font-family: var(--sans);
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--bg);
  color: var(--ink);
  outline: none;
  transition: border-color 0.15s;
}
.field input:focus, .field textarea:focus { border-color: var(--ink); }
.field textarea { min-height: 110px; resize: vertical; }
.field .hint { font-size: 12.5px; color: var(--muted); margin-top: 6px; }

.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }

.check { display: flex; align-items: flex-start; gap: 10px; font-size: 14px; cursor: pointer; }
.check input { margin-top: 4px; accent-color: var(--ink); }
.check .sub { display: block; color: var(--muted); font-size: 12.5px; }

.form-msg { margin-top: 16px; font-size: 14px; display: none; padding: 10px 14px; border: 1px solid var(--line); }
.form-msg.ok { display: block; color: var(--ink); background: var(--soft); }
.form-msg.err { display: block; color: var(--ink); background: var(--soft); border-left: 3px solid var(--ink); }

.admin-head-row { display: flex; align-items: center; justify-content: space-between; margin-bottom: 20px; }
.admin-head-row h2 { font-size: 20px; font-weight: 700; }

.table-wrap { border: 1px solid var(--line); overflow-x: auto; }
table.release-table { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 560px; }
.release-table th {
  text-align: left;
  font-weight: 600;
  font-size: 12.5px;
  letter-spacing: 0.08em;
  color: var(--muted);
  padding: 12px 14px;
  border-bottom: 1px solid var(--ink);
  background: var(--soft);
}
.release-table td { padding: 12px 14px; border-bottom: 1px solid var(--line); }
.release-table tr:last-child td { border-bottom: none; }
.release-table .mono { font-family: var(--mono); font-size: 12.5px; }
.release-table .ops { white-space: nowrap; }
.release-table .ops button, .release-table .ops a {
  font-size: 12.5px;
  padding: 4px 10px;
  border: 1px solid var(--line);
  background: var(--bg);
  cursor: pointer;
  border-radius: 3px;
  margin-right: 6px;
}
.release-table .ops a:hover { border-color: var(--ink); }
.release-table .ops button.danger:hover { background: var(--ink); color: #fff; border-color: var(--ink); }

/* ---------------- 页脚 ---------------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding: 40px 0;
  color: var(--muted);
  font-size: 13.5px;
}
.site-footer .container {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.site-footer a { border-bottom: 1px solid var(--line); }
.site-footer a:hover { color: var(--ink); border-bottom-color: var(--ink); }

/* ---------------- 响应式 ---------------- */

@media (max-width: 860px) {
  .hero h1 { font-size: 40px; }
  .hero { padding: 64px 0 56px; }
  .release-hero { grid-template-columns: 1fr; gap: 32px; padding: 40px 24px; }
  .release-hero .version { font-size: 40px; }
  .feature-grid { grid-template-columns: 1fr; }
  .section { padding: 64px 0; }
  .stats .container { grid-template-columns: repeat(3, 1fr); }
  .stat b { font-size: 26px; }
}

@media (max-width: 560px) {
  .site-nav { gap: 16px; font-size: 14px; }
  .brand span.brand-text { display: none; }
  .hero h1 { font-size: 32px; }
  .hero p.lead { font-size: 16px; }
  .btn { width: 100%; }
  .hero-actions .btn { width: auto; }
  .stats .container { grid-template-columns: 1fr; gap: 20px; }
  .page-title h1 { font-size: 30px; }
  .release-actions .btn { width: 100%; }
  .field-row { grid-template-columns: 1fr; }
}