/* ===== リセット & ベース ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --radius: 96;
  --circumference: 603.19; /* 2 * π * 96 */
}

body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', sans-serif;
  transition: background 0.6s ease;
}

/* ===== カラーテーマ ===== */
body.mode-work {
  background: linear-gradient(135deg, #c0392b 0%, #e74c3c 50%, #e67e22 100%);
  --ring-color: rgba(255, 255, 255, 0.9);
  --ring-bg: rgba(255, 255, 255, 0.2);
  --text-color: #fff;
  --btn-start-bg: rgba(255, 255, 255, 0.25);
  --btn-start-hover: rgba(255, 255, 255, 0.4);
}

body.mode-break {
  background: linear-gradient(135deg, #1a5276 0%, #2980b9 50%, #27ae60 100%);
  --ring-color: rgba(255, 255, 255, 0.9);
  --ring-bg: rgba(255, 255, 255, 0.2);
  --text-color: #fff;
  --btn-start-bg: rgba(255, 255, 255, 0.25);
  --btn-start-hover: rgba(255, 255, 255, 0.4);
}

/* ===== レイアウト ===== */
.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.2rem;
  color: var(--text-color);
  user-select: none;
}

/* ===== タイトル ===== */
.app-title {
  font-size: 1.1rem;
  font-weight: 400;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  opacity: 0.8;
}

/* ===== モードラベル ===== */
.mode-label {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  opacity: 0.9;
}

/* ===== タイマー（SVG + 数字） ===== */
.timer-wrapper {
  position: relative;
  width: 220px;
  height: 220px;
}

.progress-ring {
  width: 220px;
  height: 220px;
}

.progress-ring__bg {
  fill: none;
  stroke: var(--ring-bg);
  stroke-width: 10;
}

.progress-ring__fill {
  fill: none;
  stroke: var(--ring-color);
  stroke-width: 10;
  stroke-linecap: round;
  stroke-dasharray: 603.19;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.8s linear;
}

.time-display {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3.6rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text-color);
  font-variant-numeric: tabular-nums;
}

/* ===== セット数ラベル ===== */
.session-label {
  font-size: 0.95rem;
  opacity: 0.85;
  letter-spacing: 0.06em;
  min-height: 1.4em;
  text-align: center;
}

/* ===== ボタン ===== */
.controls {
  display: flex;
  gap: 1rem;
  margin-top: 0.4rem;
}

.btn {
  border: none;
  border-radius: 50px;
  padding: 0.75rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 0.06em;
  transition: background 0.2s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.96);
}

.btn-start {
  background: var(--btn-start-bg);
  color: #fff;
  border: 2px solid rgba(255, 255, 255, 0.6);
  min-width: 7rem;
}

.btn-start:hover {
  background: var(--btn-start-hover);
}

.btn-reset {
  background: transparent;
  color: rgba(255, 255, 255, 0.7);
  border: 2px solid rgba(255, 255, 255, 0.3);
}

.btn-reset:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border-color: rgba(255, 255, 255, 0.5);
}