* { box-sizing: border-box; }

/* ---- 顏色：淺色（預設） ---- */
:root {
  --bg: #e9ebef;
  --card: #f8f9fe;
  --card-border: #dde0e6;
  --text: #222;
  --muted: #888;
  --area-bg: #f5fff9;
  --area-text: #111;
  --area-border: #111;
  --btn-bg: #fff8c6;
  --btn-border: #ffad5c;
  --btn-text: #129412;
  --btn-hover: #ffef94;
  --accent: #e00;
  color-scheme: light;
}

/* ---- 顏色：深色 ---- */
:root[data-theme="dark"] {
  --bg: #0a0c0f;
  --card: #111418;
  --card-border: #2a2f36;
  --text: #e6e6e6;
  --muted: #8b949e;
  --area-bg: #0d1117;
  --area-text: #fff;
  --area-border: #3a414b;
  --btn-bg: #1b2028;
  --btn-border: #c27a35;
  --btn-text: #6fdc6f;
  --btn-hover: #262d37;
  --accent: #ff6b6b;
  color-scheme: dark;
}
/* 沒手動選過時，跟隨系統設定 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0a0c0f;
    --card: #111418;
    --card-border: #2a2f36;
    --text: #e6e6e6;
    --muted: #8b949e;
    --area-bg: #0d1117;
    --area-text: #fff;
    --area-border: #3a414b;
    --btn-bg: #1b2028;
    --btn-border: #c27a35;
    --btn-text: #6fdc6f;
    --btn-hover: #262d37;
    --accent: #ff6b6b;
    color-scheme: dark;
  }
}

body {
  margin: 0;
  font-family: "Microsoft JhengHei", "PingFang TC", "Noto Sans TC", sans-serif;
  background: var(--bg);
  color: var(--text);
}

main {
  max-width: 1240px;
  margin: 0 auto;
  padding: 20px 16px 48px;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
h1 { margin: 0; font-size: 1.5rem; }
h1 small { font-size: 0.9rem; color: var(--muted); font-weight: normal; }

.card {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 6px;
  padding: 20px;
  margin-bottom: 16px;
}

.buttons {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
}

textarea {
  display: block;
  width: 100%;
  height: 520px;
  margin: 12px 0;
  padding: 6px;
  font-size: 1.1rem;
  line-height: 1.5;
  font-family: inherit;
  background: var(--area-bg);
  color: var(--area-text);
  border: 3px solid var(--area-border);
  border-radius: 4px;
  resize: vertical;
}
textarea:focus { outline: none; }

button {
  padding: 8px 18px;
  font-size: 1.05rem;
  font-family: inherit;
  background: var(--btn-bg);
  color: var(--btn-text);
  border: 3px solid var(--btn-border);
  border-radius: 4px;
  cursor: pointer;
}
button:hover:not(:disabled) { background: var(--btn-hover); }
button:disabled { opacity: 0.45; cursor: default; }
button.ghost { padding: 4px 12px; font-size: 0.95rem; }

#status { color: var(--muted); font-size: 0.95rem; }

.count {
  margin: 12px 0 0;
  text-align: right;
  font-size: 1.2rem;
  color: var(--muted);
}
.count b { color: var(--accent); font-weight: normal; }
.count .hint { font-size: 0.85rem; opacity: 0.6; }

details {
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 6px;
  padding: 12px 16px;
}
summary { cursor: pointer; font-weight: bold; }
.hint { color: var(--muted); font-size: 0.9rem; }

#add-rule { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
#add-rule input {
  padding: 6px 8px;
  border: 1px solid var(--card-border);
  border-radius: 4px;
  background: var(--area-bg);
  color: var(--area-text);
  font-family: inherit;
}
.rules-io { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; margin-top: 10px; }

#add-rule button, #rules button, .rules-io button { padding: 3px 12px; font-size: 0.9rem; border-width: 2px; }

/* 最多顯示 7 行，超過時只在框內捲動 */
#rules {
  --row: 46px;
  padding: 0 8px 0 0;
  list-style: none;
  max-height: calc(var(--row) * 7);
  overflow-y: auto;
  overscroll-behavior: contain;
}
#rules li {
  display: flex;
  gap: 12px;
  align-items: center;
  height: var(--row);
  border-bottom: 1px dashed var(--card-border);
}