/* ================= 五子棋学习与对战 · 全站样式 ================= */
:root {
  --bg: #0f1420;
  --bg-soft: #161d2c;
  --card: #1b2334;
  --card-2: #212b3f;
  --line: #2c3purple;
  --line: #2c3750;
  --txt: #e8edf7;
  --txt-dim: #9aa8c2;
  --accent: #f0a33c;
  --accent-2: #4a9de0;
  --good: #45c07a;
  --bad: #e3574a;
  --radius: 14px;
  --shadow: 0 6px 28px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  background: linear-gradient(180deg, #0d121d 0%, #131a28 100%);
  color: var(--txt);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- 顶栏 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(13, 18, 29, .92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  max-width: 1240px; margin: 0 auto; padding: 12px 18px;
  display: flex; align-items: center; gap: 22px; flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 19px; color: var(--txt); }
.brand:hover { text-decoration: none; }
.brand-dot {
  width: 26px; height: 26px; border-radius: 50%;
  background: radial-gradient(circle at 32% 30%, #6b6b6b, #0b0b0b 70%);
  box-shadow: 0 0 0 3px rgba(240, 163, 60, .25);
  flex: none;
}
.main-nav { display: flex; gap: 6px; flex-wrap: wrap; }
.main-nav a {
  padding: 7px 14px; border-radius: 999px; color: var(--txt-dim);
  font-size: 15px; font-weight: 600;
}
.main-nav a:hover { background: var(--card); color: var(--txt); text-decoration: none; }
.main-nav a.active { background: var(--accent); color: #241703; }

/* ---------- 布局 ---------- */
.wrap { max-width: 1240px; margin: 0 auto; padding: 26px 18px 80px; }
.wrap-narrow { max-width: 940px; }
h1, h2, h3 { line-height: 1.3; }
h1 { font-size: 30px; margin: 0 0 10px; }
h2 { font-size: 22px; margin: 34px 0 12px; }
h3 { font-size: 17px; margin: 22px 0 8px; }
p { margin: 10px 0; }
.lead { color: var(--txt-dim); font-size: 16px; max-width: 780px; }

.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow);
}
.grid { display: grid; gap: 16px; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }

/* ---------- 按钮 / 表单 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 9px 16px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card-2); color: var(--txt); font-size: 14.5px; font-weight: 600;
  cursor: pointer; font-family: inherit; transition: .15s;
}
.btn:hover { background: #2a3550; text-decoration: none; }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #241703; }
.btn-primary:hover { background: #ffb551; }
.btn-ghost { background: transparent; }
.btn-sm { padding: 6px 11px; font-size: 13px; }
.btn-row { display: flex; gap: 9px; flex-wrap: wrap; }

select, input[type=text] {
  background: var(--bg-soft); color: var(--txt); border: 1px solid var(--line);
  border-radius: 10px; padding: 9px 12px; font-size: 15px; font-family: inherit;
}
input[type=text] { letter-spacing: 1px; }
label.field { display: block; margin: 12px 0; font-size: 14px; color: var(--txt-dim); font-weight: 600; }
label.field span { display: block; margin-bottom: 5px; }

/* ---------- 棋盘 ---------- */
.board-wrap { width: 100%; max-width: 620px; margin: 0 auto; }
.board-wrap canvas { display: block; border-radius: 10px; box-shadow: var(--shadow); cursor: pointer; touch-action: manipulation; }
.board-mini { max-width: 260px; }

.game-layout { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(280px, .85fr); gap: 22px; align-items: start; }
@media (max-width: 900px) { .game-layout { grid-template-columns: 1fr; } }

/* ---------- 状态条 ---------- */
.status-bar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 11px 15px; border-radius: 12px; background: var(--card-2);
  border: 1px solid var(--line); margin-bottom: 14px; font-size: 15px;
}
.turn-dot { width: 17px; height: 17px; border-radius: 50%; flex: none; border: 1px solid rgba(255,255,255,.25); }
.turn-dot.black { background: radial-gradient(circle at 32% 30%, #666, #0a0a0a 70%); }
.turn-dot.white { background: radial-gradient(circle at 32% 30%, #fff, #c9c9c9 70%); }

.badge {
  display: inline-block; padding: 2px 9px; border-radius: 999px;
  font-size: 12.5px; font-weight: 700; background: var(--card-2);
  border: 1px solid var(--line); color: var(--txt-dim);
}
.badge-ok { background: rgba(69,192,122,.16); border-color: rgba(69,192,122,.5); color: #7fe0a5; }
.badge-warn { background: rgba(227,87,74,.16); border-color: rgba(227,87,74,.5); color: #ff9a90; }
.badge-info { background: rgba(74,157,224,.16); border-color: rgba(74,157,224,.5); color: #8ecbff; }
.badge-accent { background: rgba(240,163,60,.18); border-color: rgba(240,163,60,.5); color: #ffc576; }

/* ---------- 走子记录 ---------- */
.move-log {
  max-height: 220px; overflow-y: auto; font-size: 13.5px;
  display: flex; flex-wrap: wrap; gap: 5px; align-content: flex-start;
}
.move-log .mv {
  padding: 2px 7px; border-radius: 6px; background: var(--bg-soft);
  border: 1px solid var(--line); font-variant-numeric: tabular-nums;
}
.move-log .mv.b { border-left: 3px solid #d8d8d8; }
.move-log .mv.w { border-left: 3px solid #6f7d96; }

/* ---------- 学习页 ---------- */
.lesson-nav { display: flex; flex-direction: column; gap: 5px; }
.lesson-nav button {
  text-align: left; padding: 10px 13px; border-radius: 10px;
  border: 1px solid transparent; background: transparent; color: var(--txt-dim);
  cursor: pointer; font-family: inherit; font-size: 14.5px; font-weight: 600;
}
.lesson-nav button:hover { background: var(--card-2); color: var(--txt); }
.lesson-nav button.active { background: var(--accent); color: #241703; border-color: var(--accent); }
.lesson-group-title {
  font-size: 12px; text-transform: uppercase; letter-spacing: .8px;
  color: #64738d; margin: 14px 0 4px; padding-left: 4px; font-weight: 700;
}

.step-box { background: var(--bg-soft); border: 1px solid var(--line); border-radius: 12px; padding: 15px; }
.step-counter { font-size: 13px; color: var(--txt-dim); font-weight: 700; }
.step-title { font-size: 17.5px; font-weight: 800; margin: 5px 0 8px; }
.step-text { font-size: 15px; }
.step-text strong { color: var(--accent); }
.verify-line {
  margin-top: 12px; padding: 9px 12px; border-radius: 9px;
  background: rgba(74,157,224,.09); border: 1px solid rgba(74,157,224,.28);
  font-size: 13.5px; color: #bcd6f2;
}
.verify-line code { color: #ffd79a; }

.coord-chip {
  display: inline-block; padding: 1px 7px; border-radius: 6px;
  background: rgba(240,163,60,.16); color: #ffc576;
  font-weight: 700; font-variant-numeric: tabular-nums; font-size: 13.5px;
}

/* 开局图谱 */
.opening-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); gap: 14px; }
.opening-card {
  background: var(--card-2); border: 1px solid var(--line); border-radius: 12px;
  padding: 11px; text-align: center; cursor: pointer; transition: .15s;
}
.opening-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.opening-card.featured { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent) inset; }
.opening-card canvas { width: 100%; height: auto; border-radius: 7px; }
.opening-name { font-weight: 800; margin-top: 7px; font-size: 15px; }
.opening-meta { font-size: 12px; color: var(--txt-dim); }

table.data { width: 100%; border-collapse: collapse; font-size: 14px; }
table.data th, table.data td { padding: 8px 10px; border-bottom: 1px solid var(--line); text-align: left; }
table.data th { color: var(--txt-dim); font-size: 12.5px; text-transform: uppercase; letter-spacing: .5px; }
table.data tr.hl td { background: rgba(240,163,60,.09); }

.note {
  border-left: 3px solid var(--accent); background: rgba(240,163,60,.07);
  padding: 11px 14px; border-radius: 0 10px 10px 0; margin: 14px 0; font-size: 14.5px;
}
.note.info { border-color: var(--accent-2); background: rgba(74,157,224,.07); }
.note.warn { border-color: var(--bad); background: rgba(227,87,74,.07); }

ul.tight { margin: 9px 0; padding-left: 22px; }
ul.tight li { margin: 5px 0; }

.hero {
  text-align: center; padding: 46px 20px 34px;
  background: radial-gradient(ellipse at 50% 0%, rgba(240,163,60,.13), transparent 62%);
}
.hero h1 { font-size: 38px; margin-bottom: 12px; }
.hero .lead { margin: 0 auto 24px; }
@media (max-width: 640px) { .hero h1 { font-size: 28px; } h1 { font-size: 24px; } }

.feature-icon { font-size: 26px; margin-bottom: 6px; }
.learn-layout { display: grid; grid-template-columns: 232px minmax(0, 1fr); gap: 24px; align-items: start; }
@media (max-width: 860px) { .learn-layout { grid-template-columns: 1fr; } }

.footer { border-top: 1px solid var(--line); padding: 22px 18px; text-align: center; color: #63718a; font-size: 13.5px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); }