:root {
  /* Color Palette - Deep Clinical Teal & Calming Mint */
  --bg-primary: #0F172A;
  --bg-secondary: #1E293B;
  --accent-primary: #2DD4BF;
  --accent-secondary: #5EEAD4;
  --text-main: #F8FAFC;
  --text-muted: #94A3B8;
  --border-color: #334155;
  --status-success: #10B981;
  --status-warning: #F59E0B;
  --card-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
  
  /* Spacing */
  --space-xs: 8px;
  --space-sm: 12px;
  --space-md: 20px;
  --space-lg: 32px;
  --space-xl: 48px;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

body {
  margin: 0;
  padding: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.5;
  overflow-x: hidden;
}

/* Layout Containers */
.mobile-container {
  max-width: 480px;
  margin: 0 auto;
  min-height: 100vh;
  background-color: var(--bg-primary);
  position: relative;
  display: flex;
  flex-direction: column;
}

.content-padding {
  padding: 0 var(--space-md);
}

/* Header */
.header-nav {
  padding: var(--space-md);
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  background-color: var(--bg-primary);
  z-index: 100;
}

.user-profile {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* Cards */
.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-md);
  box-shadow: var(--card-shadow);
  transition: transform 0.2s ease;
}

.card:active {
  transform: scale(0.98);
}

/* Progress Section */
.hero-stats {
  background: linear-gradient(135deg, #2DD4BF 0%, #0D9488 100%);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  color: white;
  margin-bottom: var(--space-lg);
  position: relative;
  overflow: hidden;
}

.hero-stats::after {
  content: '';
  position: absolute;
  top: -20%;
  right: -10%;
  width: 150px;
  height: 150px;
  background: rgba(255,255,255,0.1);
  border-radius: 50%;
}

/* Typography */
h1 { font-size: 24px; font-weight: 700; margin: 0; }
h2 { font-size: 18px; font-weight: 600; margin-bottom: var(--space-md); color: var(--text-main); }
p { font-size: 14px; color: var(--text-muted); margin: 0; }
.text-accent { color: var(--accent-primary); }

/* Buttons */
.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 24px;
  border-radius: var(--radius-md);
  font-weight: 600;
  border: none;
  cursor: pointer;
  width: 100%;
  text-decoration: none;
  font-size: 16px;
  transition: opacity 0.2s;
}

.btn-primary {
  background-color: var(--accent-primary);
  color: var(--bg-primary);
}

.btn-secondary {
  background-color: var(--bg-secondary);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

/* Tabs/Navigation Bar */
.bottom-nav {
  position: fixed;
  bottom: 0;
  width: 100%;
  max-width: 480px;
  background: rgba(30, 41, 59, 0.95);
  backdrop-filter: blur(10px);
  display: flex;
  justify-content: space-around;
  padding: 12px 0 24px 0;
  border-top: 1px solid var(--border-color);
}

.nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 12px;
}

.nav-item.active {
  color: var(--accent-primary);
}

/* Exercise Items */
.exercise-row {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--border-color);
}

.exercise-row:last-child {
  border-bottom: none;
}

.video-container {
  width: 100%;
  aspect-ratio: 16/9;
  background: #000;
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.play-btn {
  width: 64px;
  height: 64px;
  background: var(--accent-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--bg-primary);
  box-shadow: 0 0 20px rgba(45, 212, 191, 0.4);
}

.stats-grid {
  display: flex;
  justify-content: space-around;
  text-align: center;
}

.stats-divider {
  width: 1px;
  background: var(--border-color);
}

.stats-value {
  font-size: 24px;
  font-weight: 700;
  color: var(--accent-primary);
}

.stats-label {
  font-size: 12px;
  margin-bottom: 4px;
}

.placeholder-img {
  width: 60px;
  height: 60px;
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* List Items */
.list-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 0;
}

.badge {
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 12px;
  font-weight: 600;
}

.badge-success { background: rgba(16, 185, 129, 0.2); color: #34D399; }
.badge-pending { background: rgba(245, 158, 11, 0.2); color: #FBBF24; }

/* Grid for Features */
.feature-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

/* Modal/Sheet Simulation */
.sheet {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: var(--bg-secondary);
  border-top-left-radius: var(--radius-lg);
  border-top-right-radius: var(--radius-lg);
  padding: var(--space-lg);
  transform: translateY(100%);
  transition: transform 0.3s ease-out;
  z-index: 1000;
  max-width: 480px;
  margin: 0 auto;
}

.sheet.open {
  transform: translateY(0);
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: 30px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 10px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border-color);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-lg);
}

.timeline-dot {
  position: absolute;
  left: -25px;
  top: 5px;
  width: 12px;
  height: 12px;
  background: var(--accent-primary);
  border-radius: 50%;
  box-shadow: 0 0 0 4px var(--bg-primary);
}