*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --accent-work:  #e05a50;
  --accent-short: #4caf81;
  --accent-long:  #5a8fe0;
  --accent: var(--accent-work);
  --bg: #fafafa;
  --text: #1a1a1a;
  --muted: #999;
  --ring-bg: #eee;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.app {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 36px;
}

/* Mode tabs */
.modes {
  display: flex;
  gap: 4px;
  background: #eee;
  border-radius: 100px;
  padding: 4px;
}

.mode-btn {
  border: none;
  background: transparent;
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  padding: 7px 18px;
  border-radius: 100px;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  white-space: nowrap;
}

.mode-btn:hover {
  color: var(--text);
}

.mode-btn.active {
  background: #fff;
  color: var(--text);
  box-shadow: 0 1px 4px rgba(0,0,0,.1);
}

/* Timer ring */
.timer-wrap {
  position: relative;
  width: 220px;
  height: 220px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.ring {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.ring-bg {
  fill: none;
  stroke: var(--ring-bg);
  stroke-width: 6;
}

.ring-fg {
  fill: none;
  stroke: var(--accent);
  stroke-width: 6;
  stroke-linecap: round;
  stroke-dasharray: 552.92;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 1s linear, stroke 0.4s;
}

.time {
  font-size: 56px;
  font-weight: 300;
  letter-spacing: -2px;
  line-height: 1;
}

/* Controls */
.controls {
  display: flex;
  align-items: center;
  gap: 16px;
}

.btn-start {
  border: none;
  background: var(--accent);
  color: #fff;
  font-family: inherit;
  font-size: 15px;
  font-weight: 500;
  padding: 14px 48px;
  border-radius: 100px;
  cursor: pointer;
  transition: opacity 0.15s, background 0.4s;
  letter-spacing: 0.3px;
}

.btn-start:hover {
  opacity: 0.88;
}

.btn-reset {
  border: none;
  background: transparent;
  color: var(--muted);
  font-size: 22px;
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  line-height: 1;
  transition: color 0.15s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-reset:hover {
  color: var(--text);
}

/* Session dots */
.sessions {
  display: flex;
  gap: 8px;
  min-height: 10px;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ring-bg);
  transition: background 0.3s;
}

.dot.done {
  background: var(--accent);
}