:root {
  --bg-primary: #1a1a2e;
  --bg-secondary: #16213e;
  --accent: #e94560;
  --accent-glow: rgba(233, 69, 96, 0.4);
  --text-primary: #eee;
  --text-secondary: #888;
  --border-color: rgba(255, 255, 255, 0.1);
}

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

html, body {
  height: 100%;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  touch-action: manipulation;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100%;
  max-width: 500px;
  margin: 0 auto;
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.header h1 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--accent);
}

.menu-btn {
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: 0.5rem;
}

/* Main Content */
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 1.5rem;
  overflow-y: auto;
  gap: 1.5rem;
}

/* Timer */
.timer {
  font-size: 2.5rem;
  font-weight: 300;
  text-align: center;
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
}

/* Tap Area */
.tap-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  border: 2px solid var(--border-color);
  border-radius: 1rem;
  padding: 3rem 2rem;
  cursor: pointer;
  transition: transform 0.1s, border-color 0.2s;
  position: relative;
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
}

.tap-area::after {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--accent-glow);
  opacity: 0;
  transition: opacity 0.2s;
}

.tap-area:active {
  transform: scale(0.98);
  border-color: var(--accent);
}

.tap-area:active::after {
  opacity: 1;
}

.page-count {
  font-size: 5rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  position: relative;
  z-index: 1;
}

.page-label {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
  position: relative;
  z-index: 1;
}

/* Stats */
.stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1rem;
  background: var(--bg-secondary);
  border-radius: 0.75rem;
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

/* Estimate */
.estimate {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  background: var(--bg-secondary);
  border-radius: 0.75rem;
}

.estimate label {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.estimate-input {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.estimate-input input {
  width: 5rem;
  padding: 0.5rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  color: var(--text-primary);
  font-size: 1rem;
  text-align: center;
}

.estimate-input input:focus {
  outline: none;
  border-color: var(--accent);
}

.estimate-input span {
  color: var(--text-secondary);
}

.estimate-result {
  font-size: 1.25rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

/* Controls */
.controls {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-color);
  padding-bottom: max(1rem, env(safe-area-inset-bottom));
}

.control-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 0.75rem;
  color: var(--text-primary);
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.control-btn:hover {
  background: rgba(255, 255, 255, 0.05);
}

.control-btn.active {
  border-color: var(--accent);
  color: var(--accent);
}

/* Menu Overlay */
.menu-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s;
  z-index: 100;
}

.menu-overlay.open {
  opacity: 1;
  visibility: visible;
}

/* Side Menu */
.side-menu {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 280px;
  max-width: 80vw;
  background: var(--bg-secondary);
  padding: 1.5rem;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  z-index: 101;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.side-menu.open {
  transform: translateX(0);
}

.menu-close {
  align-self: flex-end;
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: 0.5rem;
  margin-bottom: 1rem;
}

.menu-item {
  width: 100%;
  padding: 1rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  color: var(--text-primary);
  font-size: 1rem;
  text-align: left;
  cursor: pointer;
  transition: border-color 0.2s;
}

.menu-item:hover {
  border-color: var(--accent);
}

.saved-sessions {
  margin-top: 1.5rem;
  flex: 1;
  overflow-y: auto;
}

.saved-sessions h3 {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

.session-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem;
  background: var(--bg-primary);
  border-radius: 0.5rem;
  margin-bottom: 0.5rem;
}

.session-info {
  font-size: 0.875rem;
}

.session-date {
  color: var(--text-secondary);
  font-size: 0.75rem;
}

.session-delete {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0.25rem;
}

.session-delete:hover {
  color: var(--accent);
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 4px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 2px;
}

/* Focus styles */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}