:root {
  --color-background: #0F172A;
  --color-foreground: #FFFFFF;
  --color-primary: #DC2626;
  --color-accent: #059669;
  --color-muted: #1F1829;
  --color-border: rgba(255, 255, 255, 0.08);
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --font-head: 'Barlow Condensed', 'Arial Narrow', system-ui, sans-serif;
  --font-body: 'Barlow', system-ui, -apple-system, 'Helvetica Neue', sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-background);
  color: var(--color-foreground);
  font-family: var(--font-body);
  font-size: 16px;
  overscroll-behavior: none;
}

body {
  max-width: 32rem;
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md) calc(var(--space-xl) + env(safe-area-inset-bottom));
  min-height: 100vh;
  min-height: 100dvh;
}

h1, h2, h3 { font-family: var(--font-head); font-weight: 700; letter-spacing: -0.01em; margin: 0 0 var(--space-md); }
h1 { font-size: 1.75rem; text-transform: uppercase; letter-spacing: 0.02em; }

.screen[hidden] { display: none !important; }

.card {
  background: var(--color-muted);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: var(--space-lg);
  margin-bottom: var(--space-md);
}

label { display: block; font-weight: 600; margin-bottom: var(--space-xs); }
.field { margin-bottom: var(--space-md); }

input[type="number"] {
  width: 100%;
  padding: 12px 16px;
  font-size: 16px;
  font-family: var(--font-body);
  background: var(--color-background);
  color: var(--color-foreground);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  transition: border-color 200ms ease, box-shadow 200ms ease;
}
input[type="number"]:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.25);
}

.tabs { display: flex; gap: var(--space-sm); margin-bottom: var(--space-md); }
.tab {
  flex: 1;
  padding: 12px;
  min-height: 44px;
  font: 600 1rem var(--font-body);
  background: transparent;
  color: var(--color-foreground);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  transition: background 200ms ease, border-color 200ms ease;
}
.tab[aria-selected="true"] { background: var(--color-primary); border-color: var(--color-primary); }

button {
  font-family: var(--font-body);
  cursor: pointer;
  touch-action: manipulation; /* 關掉行動裝置的雙擊縮放與 300ms 延遲 */
}

.hint {
  font-size: 0.85rem;
  line-height: 1.5;
  color: rgba(255, 255, 255, 0.6);
  margin: var(--space-md) 0;
}

.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  width: 100%;
  min-height: 52px;
  padding: 14px 24px;
  font: 700 1.125rem var(--font-head);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  border: 2px solid transparent;
  border-radius: 10px;
  transition: opacity 200ms ease, background 200ms ease, transform 150ms ease;
}
.btn:disabled { opacity: 0.4; cursor: not-allowed; }
.btn-primary { background: var(--color-accent); color: #fff; }
.btn-primary:not(:disabled):active { transform: translateY(1px); }
.btn-danger { background: transparent; color: var(--color-primary); border-color: var(--color-primary); }
.btn-ghost { background: transparent; color: var(--color-foreground); border-color: var(--color-border); }
.btn-row { display: flex; gap: var(--space-sm); }
.btn-row .btn { min-height: 48px; font-size: 1rem; }
/* 選中的難度檔位：實心強調色 + 勾號，跟未選的空心框拉開對比 */
.btn-row .btn[aria-pressed="true"] {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}
.btn-row .btn[aria-pressed="true"]::before { content: '✓ '; }

.checklist { list-style: none; padding: 0; margin: 0 0 var(--space-md); }
.checklist li { margin-bottom: var(--space-md); }
.checklist label { display: flex; gap: var(--space-sm); align-items: flex-start; font-weight: 500; cursor: pointer; }
.checklist input { width: 24px; height: 24px; flex: none; accent-color: var(--color-accent); }

.warn {
  border-left: 3px solid var(--color-primary);
  padding: var(--space-sm) var(--space-md);
  background: rgba(220, 38, 38, 0.08);
  border-radius: 4px;
  font-size: 0.9rem;
  line-height: 1.5;
}

.summary { font-family: var(--font-head); font-size: 1.25rem; font-weight: 600; }
.phase-list { list-style: none; padding: 0; margin: var(--space-md) 0; font-variant-numeric: tabular-nums; }
.phase-list li { display: flex; justify-content: space-between; padding: 6px 0; border-bottom: 1px solid var(--color-border); font-size: 0.95rem; }
.muted { color: rgba(255, 255, 255, 0.6); }

/* Run screen */
#run {
  position: fixed;
  inset: 0;
  height: 100dvh; /* iOS Safari：扣掉上下工具列的實際可視高度 */
  max-width: none;
  margin: 0;
  padding: calc(var(--space-lg) + env(safe-area-inset-top)) var(--space-md)
           calc(var(--space-xl) + env(safe-area-inset-bottom));
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  overflow-y: auto; /* 極小螢幕：控制列擠出去時仍可捲到 */
  background: var(--color-accent);
  transition: background 250ms ease;
  user-select: none;
  -webkit-user-select: none;
}
#run.is-hold { background: var(--color-primary); }
#run[hidden] { display: none !important; }
.run-top { text-align: center; }
.run-phase { font: 900 clamp(2rem, 12vw, 4rem) var(--font-head); text-transform: uppercase; letter-spacing: -0.03em; line-height: 1; }
.run-round { font: 600 1.25rem var(--font-head); opacity: 0.85; margin-top: var(--space-xs); }
.run-clock {
  font: 900 clamp(3rem, 22vw, 12rem) var(--font-head);
  letter-spacing: -0.05em;
  font-variant-numeric: tabular-nums;
  line-height: 1;
  transition: transform 200ms ease;
}
.run-clock.pulse { transform: scale(1.12); }
.run-next { font: 600 1rem var(--font-head); opacity: 0.8; text-align: center; }
.run-warn {
  margin: 0;
  text-align: center;
  font-size: 0.85rem;
  line-height: 1.4;
  color: #fff;
  background: rgba(0, 0, 0, 0.28);
  padding: var(--space-sm) var(--space-md);
  border-radius: 8px;
  max-width: 26rem;
}
.run-controls { display: flex; gap: var(--space-sm); width: 100%; max-width: 26rem; }
/* 計時頁背景為滿版色塊，控制鈕一律用高對比白框，不吃 .btn-danger/.btn-ghost 的顏色 */
.run-controls .btn {
  background: rgba(0, 0, 0, 0.22);
  color: #fff;
  border-color: rgba(255, 255, 255, 0.65);
}
.run-controls .btn:active { background: rgba(0, 0, 0, 0.35); }

.flash::after {
  content: '';
  position: fixed;
  inset: 0;
  background: #fff;
  opacity: 0.7;
  pointer-events: none;
  animation: flash 300ms ease-out forwards;
  z-index: 10;
}
@keyframes flash { to { opacity: 0; } }

.rpe { display: flex; flex-wrap: wrap; gap: var(--space-sm); margin: var(--space-md) 0; }
.rpe button {
  width: 44px; height: 44px;
  font: 700 1rem var(--font-head);
  background: transparent;
  color: var(--color-foreground);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  transition: background 200ms ease;
}
.rpe button[aria-pressed="true"] { background: var(--color-primary); border-color: var(--color-primary); }

.history-list { list-style: none; padding: 0; margin: 0; }
.history-list li { padding: var(--space-md) 0; border-bottom: 1px solid var(--color-border); display: flex; justify-content: space-between; gap: var(--space-md); font-variant-numeric: tabular-nums; }

.nav { display: flex; gap: var(--space-sm); margin-top: var(--space-lg); }
.nav button { flex: 1; }

/* 首頁底部說明：預設收合，不擠壓主要操作流程 */
.about { margin-top: var(--space-xl); border-top: 1px solid var(--color-border); padding-top: var(--space-lg); }
.about h2 { font-size: 1.05rem; font-weight: 600; color: rgba(255, 255, 255, 0.55); }
.about details { border-bottom: 1px solid var(--color-border); }
.about summary { padding: var(--space-md) 0; font: 600 1rem var(--font-head); letter-spacing: 0.01em; cursor: pointer; }
.about details p { margin: 0 0 var(--space-md); font-size: 0.9rem; line-height: 1.6; color: rgba(255, 255, 255, 0.7); }

@media (prefers-reduced-motion: reduce) {
  * { transition-duration: 1ms !important; animation-duration: 1ms !important; }
  .flash::after { display: none; }
  .run-clock.pulse { transform: none; }
}