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

:root {
  --bg: #0f0f0f;
  --surface: #1a1a1a;
  --border: rgba(255, 255, 255, 0.08);
  --text: #ffffff;
  --muted: rgba(255, 255, 255, 0.45);
  --accent: #ff6b35;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  overflow: hidden;
}

.back-link {
  position: fixed;
  top: 1.2rem;
  left: 1.5rem;
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s ease;
  z-index: 10;
}

.back-link:hover {
  color: var(--text);
}

#install-btn {
  position: fixed;
  top: 1.2rem;
  right: 1.5rem;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 0;
  z-index: 10;
  transition: color 0.2s ease;
  -webkit-tap-highlight-color: transparent;
}

#install-btn:hover {
  color: var(--text);
}

#app {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100dvh;
  padding: 5rem 1.5rem 2rem;
  gap: 2rem;
}

#mode-nav {
  display: flex;
  gap: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.mode-btn {
  background: transparent;
  border: none;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  padding: 0.5rem 1.25rem;
  cursor: pointer;
  transition: color 0.15s, background 0.15s;
}

.mode-btn.active {
  background: var(--accent);
  color: #000;
}

#display {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}

#phase-label {
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--muted);
  min-height: 1.2em;
  transition: color 0.2s;
}

#phase-label.work {
  color: var(--accent);
}

#phase-label.rest {
  color: #60a5fa;
}

#phase-label.ready {
  color: #a3e635;
}

#round-counter {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  min-height: 1.2em;
}

#time-display {
  font-size: clamp(5rem, 22vw, 9rem);
  font-weight: 300;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  line-height: 1;
  color: var(--text);
  transition: color 0.2s;
}

#time-display.running {
  color: var(--accent);
}

#simple-settings {
  display: flex;
  flex-direction: column;
  align-items: center;
}

#simple-settings[hidden] { display: none; }

.duration-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.adj-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 0.45rem 0.65rem;
  border-radius: 6px;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}

.adj-btn:hover {
  color: var(--text);
  border-color: rgba(255,255,255,0.2);
}

#simple-input {
  width: 5.5rem;
  text-align: center;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 1.2rem;
  font-weight: 400;
  font-variant-numeric: tabular-nums;
  padding: 0.4rem 0.5rem;
  border-radius: 6px;
  outline: none;
  transition: border-color 0.15s;
}

#simple-input:focus {
  border-color: var(--accent);
}

#interval-settings {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  width: 100%;
  max-width: 280px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.25rem;
}

#interval-settings[hidden] { display: none; }

.setting-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.setting-row label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  white-space: nowrap;
}

.setting-row input[type="text"],
.setting-row input[type="number"] {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  padding: 0.3rem 0.5rem;
  border-radius: 5px;
  outline: none;
  transition: border-color 0.15s;
  width: 5rem;
  text-align: center;
}

.setting-row input[type="text"]:focus,
.setting-row input[type="number"]:focus {
  border-color: var(--accent);
}

.setting-row input[type="checkbox"] {
  width: 1.1rem;
  height: 1.1rem;
  accent-color: var(--accent);
  cursor: pointer;
}


#controls {
  display: flex;
  gap: 1rem;
}

#start-btn, #reset-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  padding: 0.75rem 2rem;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

#start-btn {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
}

#start-btn:hover {
  filter: brightness(1.1);
}

#start-btn.paused {
  background: var(--surface);
  border-color: var(--accent);
  color: var(--accent);
}

#reset-btn:hover {
  border-color: rgba(255,255,255,0.2);
  color: var(--text);
}