/* 圓潤現代深色主題 */
:root {
  --bg: #0b1220;            /* 深色背景（方案A） */
  --bg-grad-1: #0b1220;
  --bg-grad-2: #111827;
  --panel: #121826;         /* 面板純色，簡約易讀 */
  --panel-solid: #121826;
  --text: #eef2f7;
  --muted: #b7c0cc;         /* 次要文字更柔和但清晰 */
  --primary: #2dd4bf;       /* 主色：青綠 */
  --accent: #7c3aed;        /* 輔色：紫 */
  --border: rgba(255,255,255,0.12); /* 邊框對比適中 */
  --focus-ring: rgba(45,212,191,0.45);
  --radius: 12px;           /* 統一圓角 */
  --shadow: 0 6px 16px rgba(0,0,0,0.30); /* 統一陰影 */
  --control-h: 46px; /* 控制 select 與按鈕一致高度 */
  color-scheme: dark; /* 提示瀏覽器使用深色表單控制樣式 */
}

* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0; color: var(--text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, "Noto Sans TC", Helvetica, Arial;
  background: radial-gradient(1200px 640px at 10% 12%, #121a3a 0%, var(--bg-grad-1) 45%, var(--bg-grad-2) 100%), var(--bg);
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}

.container { max-width: 960px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  border-bottom: 1px solid var(--border);
  backdrop-filter: saturate(1.15) blur(8px);
  background: linear-gradient(180deg, rgba(17,24,39,0.75), rgba(17,24,39,0.55));
}
.site-header .container { padding: 28px 20px; }
.site-header h1 { margin: 0; font-size: 30px; letter-spacing: 0.3px; }
.subtitle { margin: 6px 0 0; color: var(--muted); }

/* Footer */
.site-footer { border-top: 1px solid var(--border); margin-top: 28px; }
.site-footer .container { padding: 18px 20px; color: var(--muted); }

/* Panels / Cards */
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin: 20px 0;
  box-shadow: var(--shadow);
}
.panel h2 { margin: 0 0 12px; font-size: 20px; letter-spacing: 0.2px; }

/* Grid & Form */
.row { display: flex; flex-wrap: wrap; gap: 16px; align-items: stretch; }
.field { flex: 1 1 280px; }
.field label { display: block; margin-bottom: 8px; color: var(--muted); }
select {
  width: 100%; padding: 13px 16px; border-radius: 16px;
  border: 1px solid var(--border);
  background: linear-gradient(180deg, #101936, #0b1428);
  background-color: #0b1428; /* 明確設置深色背景，避免白底導致白字不可讀 */
  color: var(--text);
  outline: none;
  transition: box-shadow 180ms ease, transform 120ms ease;
  height: var(--control-h);
}
select:focus { box-shadow: 0 0 0 3px var(--focus-ring); }
select option {
  background-color: #0b1428; /* 下拉選單的項目背景也設為深色（部分瀏覽器可用）*/
  color: var(--text);
}
/* Actions: 兩個按鈕對齊 */
.actions {
  display: grid; grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px; align-items: stretch; flex: 1 1 320px;
  margin-top: 28px; /* 輕微下移按鈕位置 */
}

/* Buttons */
.btn {
  width: 100%;
  display: inline-block;
  padding: 12px 16px; /* 原 10px 14px，略增內邊距 */
  border-radius: 16px;
  text-decoration: none;
  font-weight: 700;
  font-size: 14px; /* 字體大小一致，移除重複設定 */
  letter-spacing: 0.2px;
  border: 1px solid rgba(255,255,255,0.16);
  color: #ffffff; /* 提升按鈕文字對比 */
  background: linear-gradient(135deg, #5eead4, #2dd4bf 55%, #14b8a6);
  box-shadow: 0 10px 28px rgba(20, 184, 166, 0.35);
  transition: transform 120ms ease, filter 160ms ease, box-shadow 160ms ease;
  text-align: center;
  height: var(--control-h);
  display: inline-flex; /* 改為 inline-flex 以便垂直置中 */
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
.btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
.btn:active { transform: translateY(0); filter: brightness(1.02); }
.btn:focus-visible { outline: 2px solid transparent; box-shadow: 0 0 0 3px var(--focus-ring); }

.btn-secondary {
  color: white;
  background: linear-gradient(135deg, #c4b5fd, #a78bfa 55%, #7c3aed);
  box-shadow: 0 10px 28px rgba(167, 139, 250, 0.35);
  border-color: rgba(255,255,255,0.16);
}

/* Tertiary: 藍色系，與訂閱按鈕區分 */
.btn-tertiary {
  color: white;
  background: linear-gradient(135deg, #60a5fa, #3b82f6 55%, #1d4ed8);
  box-shadow: 0 10px 28px rgba(59, 130, 246, 0.35);
  border-color: rgba(255,255,255,0.16);
}

/* Text helpers */
.hint, .note { color: var(--muted); margin: 10px 0 0; }
.note { font-style: italic; }

/* Inline code 提升對比 */
code {
  background-color: #0b1428;
  color: #e5e7eb;
  padding: 2px 6px;
  border-radius: 6px;
  border: 1px solid rgba(255,255,255,0.12);
}

/* Events list */
.events { display: grid; grid-template-columns: 1fr; gap: 12px; }
.event-item {
  border: 1px solid var(--border);
  border-radius: var(--radius); padding: 12px 14px;
  background: var(--panel-solid);
  box-shadow: var(--shadow);
  transition: transform 120ms ease, box-shadow 160ms ease;
}
.event-item:hover { transform: translateY(-1px); box-shadow: 0 8px 20px rgba(0, 0, 0, 0.38); }
.event-item .date { color: var(--muted); font-size: 12px; letter-spacing: 0.2px; }
.event-item .summary { font-weight: 700; margin-top: 6px; }
.event-item .time { color: var(--muted); font-size: 12px; }

@media (max-width: 639px) {
  .actions { grid-template-columns: 1fr; }
}
@media (min-width: 640px) {
  .events { grid-template-columns: 1fr 1fr; }
}
@media (min-width: 1024px) {
  .events { grid-template-columns: 1fr 1fr 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

/* Apple HIG 風格覆寫：輕量、清晰、以內容為中心 */
:root {
  color-scheme: light dark;
  --bg: #F2F2F7;              /* iOS 系統群組背景 */
  --bg-grad-1: #F2F2F7;
  --bg-grad-2: #EFEFF4;
  --panel: #FFFFFF;           /* 群組卡片背景 */
  --panel-solid: #FFFFFF;
  --text: #1C1C1E;            /* 系統文字 */
  --muted: #6E6E73;           /* 次要文字 */
  --primary: #0A84FF;         /* System Blue */
  --accent: #5856D6;          /* System Indigo */
  --border: rgba(0,0,0,0.12); /* 細緻分隔線 */
  --focus-ring: rgba(10,132,255,0.45);
  --radius: 12px;             /* 圓角一致 */
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 8px 24px rgba(0,0,0,0.06);
  --control-h: 44px;          /* 最小觸控高度 */
}

html, body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "Noto Sans TC", Helvetica, Arial, sans-serif;
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* 導覽列：透明模糊與安全區 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  padding-top: env(safe-area-inset-top);
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.80);
  backdrop-filter: saturate(1.1) blur(12px);
}
.site-header .container { padding: 20px; }
.site-header h1 { font-weight: 700; letter-spacing: 0.2px; }
.subtitle { color: var(--muted); }

/* 卡片與群組 */
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.panel h2 { font-size: 18px; font-weight: 700; }

/* 表單控制：淺色預設、深色覆寫於下 */
select {
  background: #FFFFFF;
  color: var(--text);
  border: 1px solid var(--border);
  height: var(--control-h);
}
select:focus { box-shadow: 0 0 0 3px var(--focus-ring); }

/* 動作區佈局保持不變 */

/* 按鈕：實心、低裝飾、清晰層級 */
.btn {
  background: var(--primary);
  border: 1px solid rgba(0,0,0,0.08);
  color: #FFFFFF;
  font-weight: 600;
  border-radius: 12px;
  height: var(--control-h);
  box-shadow: 0 2px 6px rgba(10,132,255,0.20);
}
.btn:hover { filter: brightness(1.06); }
.btn:active { filter: brightness(0.98); }
.btn:focus-visible { outline: 2px solid transparent; box-shadow: 0 0 0 3px var(--focus-ring); }

.btn-secondary {
  background: var(--accent);
  border-color: rgba(0,0,0,0.08);
  box-shadow: 0 2px 6px rgba(88,86,214,0.20);
}

.btn-tertiary {
  background: #34C759; /* System Green for tertiary */
  border-color: rgba(0,0,0,0.08);
  box-shadow: 0 2px 6px rgba(52,199,89,0.20);
}

/* 文字與代碼區的對比 */
code {
  background-color: #FFFFFF;
  color: #1C1C1E;
  border: 1px solid var(--border);
}

/* 事件列表：視覺層次更輕、更清晰 */
.event-item {
  background: var(--panel-solid);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.event-item .date { color: var(--muted); font-size: 12px; }
.event-item .summary { font-weight: 700; }
.event-item .time { color: var(--muted); }

/* 深色模式覆寫：延續原主題但更符合 HIG 對比 */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --bg-grad-1: #0b1220;
    --bg-grad-2: #111827;
    --panel: #121826;
    --panel-solid: #121826;
    --text: #eef2f7;
    --muted: #b7c0cc;
    --primary: #0A84FF;
    --accent: #7c3aed;
    --border: rgba(255,255,255,0.12);
    --focus-ring: rgba(10,132,255,0.45);
    --shadow: 0 6px 16px rgba(0,0,0,0.30);
  }
  html, body {
    background: radial-gradient(1200px 640px at 10% 12%, #121a3a 0%, var(--bg-grad-1) 45%, var(--bg-grad-2) 100%), var(--bg);
  }
  .site-header {
    background: linear-gradient(180deg, rgba(17,24,39,0.75), rgba(17,24,39,0.55));
    backdrop-filter: saturate(1.15) blur(8px);
    border-bottom: 1px solid var(--border);
  }
  select {
    background: linear-gradient(180deg, #101936, #0b1428);
    color: var(--text);
    border: 1px solid var(--border);
  }
  code {
    background-color: #0b1428;
    color: #e5e7eb;
    border: 1px solid rgba(255,255,255,0.12);
  }
}

/* 安全區補強：部分瀏覽器支援 */
@supports (padding: env(safe-area-inset-top)) {
  .site-header { padding-top: calc(env(safe-area-inset-top) + 8px); }
}

/* Header 右上角作者配置 */
.site-header .container { display: flex; justify-content: space-between; align-items: center; }
.brand { display: flex; flex-direction: column; gap: 6px; }
.author { color: var(--muted); font-size: 14px; font-weight: 600; }

/* Header 次行説明樣式 */
.subnote { color: var(--muted); font-size: 14px; margin-top: 4px; }