/* 统一深色模式 + 大字体 */
:root {
  --bg: #0f1115;
  --bg-elev: #161a21;
  --text: #e6e6e6;
  --muted: #a8b0be;
  --accent: #3aa0ff;
  --accent-2: #7c4dff;
  --danger: #ff4d4f;
  --ok: #4caf50;
  --border: #2a2f3a;
  --shadow: 0 10px 24px rgba(0,0,0,.45);
  --radius: 14px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, PingFang SC, Microsoft YaHei, 'Noto Sans SC', sans-serif;
  font-size: 36px; /* 强制大字 */
  line-height: 1.4;
}

.container {
  max-width: 980px;
  margin: 24px auto;
  padding: 0 20px;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 20px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.title {
  font-size: 36px;
  font-weight: 700;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: #1b2030;
  color: #fff; /* 强制按钮文字为白色 */
  padding: 10px 16px;
  border-radius: 12px;
  cursor: pointer;
  font-size: 36px;
  transition: all .15s ease;
}
.btn:hover { border-color: var(--accent); color: #fff; }
.btn:active { transform: translateY(1px); }

.btn-primary { background: linear-gradient(180deg, #1f2436, #1b2030); border-color: #2d3650; }
.btn-accent { background: #1b2840; border-color: #30518f; color: #fff; }
.btn-danger { background: #3a1b1e; border-color: #6b2b31; color: #fff; }
.btn-ok { background: #153524; border-color: #2b6c4b; color: #fff; }

.card {
  margin-top: 18px;
  padding: 18px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.prompt { font-size: 36px; margin-bottom: 14px; }
.options { display: grid; grid-template-columns: 1fr; gap: 12px; }
@media (min-width: 680px) { .options { grid-template-columns: 1fr 1fr; } }
.option {
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #151a24;
  color: #fff; /* 选项按钮文字为白色 */
  cursor: pointer;
  font-size: 36px;
}
.option:hover { border-color: var(--accent); }
.option.correct { border-color: var(--ok); background: #142419; }
.option.wrong { border-color: var(--danger); background: #2a1517; }

.meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 12px;
  color: var(--muted);
}

.kbd {
  display: inline-block;
  padding: 2px 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #131722;
  font-size: 36px;
}

.footer { margin-top: 22px; color: var(--muted); }

.rule {
  white-space: pre-wrap;
  background: #12151e;
  border: 1px dashed var(--border);
  padding: 12px;
  border-radius: 12px;
}

.badge { display: inline-block; padding: 2px 10px; border-radius: 999px; font-size: 36px; }
.badge-neutral { background: #2a2f3a; color: #dfe6f3; }
.badge-pos { background: #153524; color: #c6ffe2; }
.badge-neg { background: #3a1b1e; color: #ffd8d9; }

.stats { display: flex; gap: 10px; flex-wrap: wrap; }
.stats .item { background: #131722; border: 1px solid var(--border); border-radius: 10px; padding: 8px 10px; }

.hidden { display: none; }

/* --- Layout & Typography (shared) --- */
main{max-width:960px;margin:0 auto;padding:0 24px 32px}
header h1{margin:16px 24px;font-size:36px;color:#fff}
#levels-title{margin:0 0 12px;padding:12px 0;color:#fff;font-size:36px}
footer{text-align:center;color:#9aa0a6;padding:16px 0 24px}

/* --- Index: two-column level cards --- */
ol.levels{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(2,minmax(280px,1fr));gap:20px}
ol.levels>li{list-style:none}
a.level{display:block;text-decoration:none;text-align:center;padding:24px 20px;border-radius:12px;border:2px solid #2b2b2b;background:#0f0f10;color:#d6d6d6;box-shadow:0 2px 8px rgba(0,0,0,.35);transition:transform .15s ease,box-shadow .15s ease,border-color .15s ease,background .15s ease}
a.level:hover{transform:translateY(-2px);border-color:#2fa36a;box-shadow:0 6px 16px rgba(47,163,106,.25);background:#111213}
a.level:focus{outline:3px solid #2fa36a;outline-offset:2px}
.level-name{display:block;font-size:36px;font-weight:800;color:#23c160;letter-spacing:.5px}
.level-subtitle{display:block;margin-top:8px;font-size:36px;color:#c9c9c9}
@media(max-width:640px){ol.levels{grid-template-columns:1fr}}

/* --- Game pages: cards & options --- */
p.meta{color:#c9c9c9;margin:8px 0 16px}
section.card{border:2px solid #2b2b2b;border-radius:12px;background:#0f0f10;color:#d6d6d6;box-shadow:0 2px 8px rgba(0,0,0,.35);padding:20px;margin:0 0 16px}
p.prompt{font-size:36px;color:#e6e6e6;margin:0 0 12px;font-weight:600}
ul.options{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:1fr;gap:10px}
button.option{display:block;width:100%;text-align:center;padding:12px 14px;border-radius:8px;border:2px solid #2b2b2b;background:#151516;color:#d6d6d6;cursor:pointer;transition:transform .12s ease,border-color .12s ease,background .12s ease}
button.option:hover{transform:translateY(-1px);border-color:#2fa36a;background:#18191a}
button.option:focus{outline:3px solid #2fa36a;outline-offset:2px}

/* Generic button for actions */
.btn{display:inline-block;padding:10px 14px;border-radius:8px;border:2px solid #2b2b2b;background:#151516;color:#d6d6d6;text-decoration:none;cursor:pointer}
.btn:hover{border-color:#2fa36a;background:#18191a}