/* ==========================================================================
   BackFix — Fitness Rehabilitation App Stylesheet
   Theme: Dark Theme (Rehab / Medical / Fitness)
   Architecture: Mobile-First Responsive Design
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Custom Properties (Theme Variables)
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette */
  --bg-color: #1a1a2e;           /* Deep Charcoal Background */
  --surface-color: #16213e;      /* Dark Navy Surface / Cards */
  --surface-hover: #1a2745;      /* Elevated / Hover Surface */
  --surface-active: #1e2e52;     /* Pressed Surface */

  /* Accents & States */
  --primary: #0f9b8e;            /* Warm Teal Primary Accent */
  --primary-hover: #12b3a4;      /* Brighter Teal on Hover */
  --primary-rgb: 15, 155, 142;   /* RGB for alpha variations */
  --success: #27ae60;            /* Emerald Green for Completed */
  --success-rgb: 39, 174, 96;    /* RGB for alpha variations */
  --warning: #f39c12;            /* Amber for Timers / Mid-level pain */
  --warning-rgb: 243, 156, 18;   /* RGB for alpha variations */
  --danger: #e74c3c;             /* Crimson for High Pain / Destructive */
  --danger-rgb: 231, 76, 60;     /* RGB for alpha variations */

  /* Typography */
  --text-primary: #e8e8e8;        /* Off-white Headings & High Contrast */
  --text-secondary: #a0a0b8;      /* Soft Grey Secondary Text */
  --text-muted: #6c6c80;          /* Muted Captions & Placeholders */

  /* Borders & Dividers */
  --border-color: #2a2a4a;        /* Subtle Navy / Charcoal Border */
  --border-light: #35355a;        /* Highlight Border */

  /* Layout & Sizing */
  --max-width: 600px;
  --header-height: 64px;
  --bottom-nav-height: 68px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-pill: 20px;
  --radius-full: 50%;

  /* Safe Area Insets for Mobile Notches */
  --sab: env(safe-area-inset-bottom, 0px);
  --sat: env(safe-area-inset-top, 0px);
}

/* --------------------------------------------------------------------------
   2. Reset & Base Styles
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  color-scheme: dark;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-color);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  color: var(--text-primary);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Custom Dark Scrollbar (Webkit & Standard) */
html {
  scrollbar-width: thin;
  scrollbar-color: var(--border-color) var(--bg-color);
}

::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--primary);
}

/* --------------------------------------------------------------------------
   3. Main App Layout & Header
   -------------------------------------------------------------------------- */
.app {
  max-width: var(--max-width);
  margin: 0 auto;
  min-height: 100vh;
  padding-bottom: calc(var(--bottom-nav-height) + 12px + var(--sab));
  position: relative;
  background-color: var(--bg-color);
}

.header {
  position: sticky;
  top: 0;
  background: rgba(22, 33, 62, 0.92);
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header h1 {
  font-size: 1.3rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-primary);
  letter-spacing: -0.3px;
  margin: 0;
}

.header .phase-badge {
  background-color: var(--primary);
  color: #ffffff;
  border-radius: var(--radius-pill);
  padding: 4px 12px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.2px;
  box-shadow: 0 2px 8px rgba(15, 155, 142, 0.35);
  white-space: nowrap;
}

/* --------------------------------------------------------------------------
   4. Bottom Navigation Bar
   -------------------------------------------------------------------------- */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  background: rgba(22, 33, 62, 0.95);
  display: flex;
  justify-content: space-around;
  align-items: center;
  padding: 8px 0 calc(8px + var(--sab));
  border-top: 1px solid var(--border-color);
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.nav-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  background: none;
  border: none;
  color: var(--text-secondary);
  padding: 8px 16px;
  cursor: pointer;
  transition: color 0.2s ease, transform 0.15s ease;
  user-select: none;
  text-decoration: none;
}

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

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

.nav-btn .nav-icon {
  font-size: 1.3rem;
  line-height: 1;
}

.nav-btn .nav-label {
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   5. Tab Content Management
   -------------------------------------------------------------------------- */
.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

/* --------------------------------------------------------------------------
   6. Pain Check-in Section
   -------------------------------------------------------------------------- */
.pain-checkin {
  margin: 16px 20px;
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  border: 1px solid var(--border-color);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
}

.pain-checkin h3 {
  margin: 0 0 12px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.pain-scale {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 4px;
}

.pain-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border-color);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: bold;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  user-select: none;
  padding: 0;
}

.pain-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
}

.pain-btn.selected {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  transform: scale(1.1);
  box-shadow: 0 0 10px rgba(var(--primary-rgb), 0.4);
}

/* Pain Level Variations when Selected */
.pain-btn.low.selected,
.pain-btn.selected.low {
  background: var(--success);
  border-color: var(--success);
  color: #ffffff;
  box-shadow: 0 0 10px rgba(var(--success-rgb), 0.4);
}

.pain-btn.medium.selected,
.pain-btn.selected.medium {
  background: var(--warning);
  border-color: var(--warning);
  color: #ffffff;
  box-shadow: 0 0 10px rgba(var(--warning-rgb), 0.4);
}

.pain-btn.high.selected,
.pain-btn.selected.high {
  background: var(--danger);
  border-color: var(--danger);
  color: #ffffff;
  box-shadow: 0 0 10px rgba(var(--danger-rgb), 0.4);
}

.pain-labels {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 8px;
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   7. Workout Section & Header
   -------------------------------------------------------------------------- */
.workout-header {
  padding: 16px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.workout-header h2 {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.workout-duration {
  font-size: 0.8rem;
  color: var(--text-secondary);
  background: var(--surface-color);
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-color);
  font-weight: 500;
}

.workout-complete-banner {
  margin: 16px 20px;
  background: linear-gradient(135deg, #27ae60, #2ecc71);
  border-radius: var(--radius-lg);
  padding: 20px;
  text-align: center;
  color: #ffffff;
  animation: fadeInUp 0.5s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: 0 8px 24px rgba(39, 174, 96, 0.35);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   8. Exercise Cards & Collapsible Content
   -------------------------------------------------------------------------- */
.exercise-card {
  margin: 8px 20px;
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  overflow: hidden;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.exercise-card.completed {
  border-color: var(--success);
  opacity: 0.7;
}

.exercise-card.completed .exercise-header {
  background: rgba(39, 174, 96, 0.1);
}

.exercise-header {
  padding: 16px;
  display: flex;
  gap: 12px;
  align-items: center;
  cursor: pointer;
  user-select: none;
  transition: background-color 0.2s ease;
}

.exercise-header:hover {
  background-color: var(--surface-hover);
}

.exercise-checkbox {
  width: 28px;
  height: 28px;
  min-width: 28px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  color: transparent;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 14px;
  line-height: 1;
  padding: 0;
}

.exercise-card.completed .exercise-checkbox {
  background: var(--success);
  border-color: var(--success);
  color: #ffffff;
}

.exercise-info {
  flex: 1;
  min-width: 0;
}

.exercise-name {
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 2px;
  color: var(--text-primary);
}

.exercise-prescription {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.exercise-type-badge {
  font-size: 0.65rem;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(15, 155, 142, 0.15);
  color: var(--primary);
  font-weight: 600;
  display: inline-block;
  white-space: nowrap;
}

.exercise-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
}

.exercise-card.expanded .exercise-body {
  max-height: 800px;
}

.exercise-details {
  padding: 0 16px 16px;
  border-top: 1px solid rgba(42, 42, 74, 0.5);
  margin-top: 4px;
  padding-top: 12px;
}

.exercise-instructions {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 12px;
}

.exercise-instructions ol {
  padding-left: 20px;
  margin: 0;
}

.exercise-instructions li {
  margin-bottom: 6px;
}

/* --------------------------------------------------------------------------
   9. Set Tracker
   -------------------------------------------------------------------------- */
.set-tracker {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
  align-items: center;
}

.set-tracker label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  min-width: 40px;
  font-weight: 500;
}

.set-dot {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border-color);
  background: transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  padding: 0;
}

.set-dot.done {
  background: var(--primary);
  border-color: var(--primary);
  box-shadow: 0 0 8px rgba(var(--primary-rgb), 0.4);
}

.set-dot:hover {
  border-color: var(--primary);
}

/* --------------------------------------------------------------------------
   10. Exercise Timer Section
   -------------------------------------------------------------------------- */
.timer-section {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.timer-display {
  font-size: 1.8rem;
  font-weight: 700;
  font-family: 'SF Mono', 'Fira Code', 'Roboto Mono', Menlo, monospace;
  color: var(--warning);
  min-width: 65px;
  text-align: center;
  letter-spacing: 1px;
  transition: color 0.3s ease;
}

@keyframes timerPulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.15); }
  100% { transform: scale(1); }
}

.timer-display.timer-done {
  color: #27ae60 !important;
  animation: timerPulse 0.4s ease 3;
}

.timer-btn {
  padding: 8px 16px;
  border-radius: var(--radius-md);
  border: none;
  font-weight: 600;
  cursor: pointer;
  font-size: 0.8rem;
  transition: all 0.2s ease;
  user-select: none;
}

.timer-btn.start {
  background: var(--primary);
  color: #ffffff;
}

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

.timer-btn.pause {
  background: var(--warning);
  color: #1a1a2e;
}

.timer-btn.pause:hover {
  filter: brightness(1.1);
}

.timer-btn.reset {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.timer-btn.reset:hover {
  border-color: var(--text-secondary);
  color: var(--text-primary);
}

/* --------------------------------------------------------------------------
   11. Video Button & Video Modal
   -------------------------------------------------------------------------- */
.video-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: rgba(15, 155, 142, 0.15);
  border: 1px solid rgba(15, 155, 142, 0.3);
  border-radius: var(--radius-md);
  color: var(--primary);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.video-btn:hover {
  background: rgba(15, 155, 142, 0.25);
  border-color: var(--primary);
}

.video-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.85);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.video-modal-overlay.active {
  opacity: 1;
  pointer-events: all;
}

.video-modal {
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 560px;
  overflow: hidden;
  border: 1px solid var(--border-color);
  box-shadow: 0 20px 48px rgba(0, 0, 0, 0.55);
}

.video-modal-header {
  padding: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
}

.video-modal-header h3 {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.video-modal-close {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 4px 8px;
  line-height: 1;
  border-radius: var(--radius-sm);
  transition: color 0.2s ease;
}

.video-modal-close:hover {
  color: var(--text-primary);
}

.video-modal-body {
  padding: 0;
  background: #000000;
}

.video-modal-body iframe {
  width: 100%;
  aspect-ratio: 16 / 9;
  border: none;
  display: block;
}

.video-modal-body .video-link {
  display: block;
  padding: 16px;
  text-align: center;
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
  background: var(--surface-color);
  border-top: 1px solid var(--border-color);
  transition: color 0.2s ease;
}

.video-modal-body .video-link:hover {
  text-decoration: underline;
  color: var(--primary-hover);
}

/* --------------------------------------------------------------------------
   12. Progress Tab & Statistics
   -------------------------------------------------------------------------- */
.progress-section {
  padding: 20px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 24px;
}

.stat-card {
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  text-align: center;
  border: 1px solid var(--border-color);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.7rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-top: 4px;
  font-weight: 600;
}

/* Phase Progress Bar */
.phase-progress {
  margin-bottom: 24px;
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  border: 1px solid var(--border-color);
}

.phase-progress h3 {
  margin: 0 0 12px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.phase-bar {
  height: 8px;
  background: #2a2a4a;
  border-radius: 4px;
  overflow: hidden;
}

.phase-fill {
  height: 100%;
  background: linear-gradient(90deg, #0f9b8e, #27ae60);
  border-radius: 4px;
  transition: width 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

.phase-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 8px;
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* Pain Trend Chart */
.pain-trend {
  margin-bottom: 24px;
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  border: 1px solid var(--border-color);
}

.pain-trend h3 {
  margin: 0 0 12px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.pain-chart {
  height: 120px;
  position: relative;
  display: flex;
  align-items: flex-end;
  gap: 4px;
  padding: 0 4px;
}

.pain-bar {
  flex: 1;
  background: rgba(15, 155, 142, 0.3);
  border-radius: 4px 4px 0 0;
  transition: height 0.3s ease, background-color 0.2s ease;
  min-height: 4px;
  position: relative;
}

.pain-bar:hover {
  background: rgba(15, 155, 142, 0.6);
}

.pain-bar .pain-bar-label {
  position: absolute;
  top: -18px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.65rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.pain-chart-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 8px;
  font-size: 0.65rem;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   13. Calendar Heatmap
   -------------------------------------------------------------------------- */
.calendar-section {
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  border: 1px solid var(--border-color);
}

.calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.calendar-header h3 {
  margin: 0;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.calendar-nav {
  display: flex;
  gap: 8px;
}

.calendar-nav button {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.2s ease;
}

.calendar-nav button:hover {
  border-color: var(--primary);
  color: var(--text-primary);
}

.calendar-weekdays {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 4px;
  margin-bottom: 4px;
}

.calendar-weekday {
  text-align: center;
  font-size: 0.65rem;
  color: var(--text-muted);
  padding: 4px 0;
  font-weight: 600;
  text-transform: uppercase;
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 4px;
}

.calendar-day {
  aspect-ratio: 1;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
}

.calendar-day.empty {
  background: transparent;
  cursor: default;
}

.calendar-day.completed {
  background: #27ae60;
  color: #ffffff;
  font-weight: 600;
}

.calendar-day.rest {
  background: #2a2a4a;
  color: var(--text-muted);
}

.calendar-day.today {
  border: 2px solid var(--primary);
  font-weight: 700;
}

.calendar-day.future {
  background: #2a2a4a;
  color: var(--text-muted);
  opacity: 0.4;
  cursor: not-allowed;
}

.calendar-legend {
  display: flex;
  gap: 16px;
  margin-top: 12px;
  justify-content: center;
  font-size: 0.7rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.legend-dot {
  width: 12px;
  height: 12px;
  border-radius: 4px;
}

.legend-dot.completed {
  background: #27ae60;
}

.legend-dot.rest {
  background: #2a2a4a;
}

.legend-dot.today {
  border: 2px solid var(--primary);
}

/* --------------------------------------------------------------------------
   14. Library Tab
   -------------------------------------------------------------------------- */
.library-section {
  padding: 20px;
}

.library-section h2 {
  margin: 0 0 16px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.library-phase-group {
  margin-bottom: 24px;
}

.library-phase-title {
  font-size: 0.85rem;
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
  letter-spacing: 0.3px;
}

.library-exercise {
  background: var(--surface-color);
  border-radius: var(--radius-md);
  padding: 14px;
  margin-bottom: 8px;
  border: 1px solid var(--border-color);
  cursor: pointer;
  transition: all 0.2s ease;
}

.library-exercise:hover {
  border-color: var(--primary);
  background-color: var(--surface-hover);
}

.library-exercise h4 {
  margin: 0 0 4px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.library-exercise p {
  margin: 0;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* --------------------------------------------------------------------------
   15. Settings & Day Picker
   -------------------------------------------------------------------------- */
.day-picker-section {
  margin: 16px 20px;
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  border: 1px solid var(--border-color);
}

.day-picker-section h3 {
  margin: 0 0 12px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.day-picker {
  display: flex;
  gap: 6px;
  justify-content: space-between;
  align-items: center;
}

.day-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border-color);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  user-select: none;
  padding: 0;
}

.day-toggle.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(var(--primary-rgb), 0.35);
}

.day-toggle:hover {
  border-color: var(--primary);
}

/* --------------------------------------------------------------------------
   Reminder Settings Section
   -------------------------------------------------------------------------- */
.reminder-section {
  margin: 16px 20px;
  background: var(--surface-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  border: 1px solid var(--border-color);
}

.reminder-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.reminder-title-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}

.reminder-icon {
  font-size: 1.3rem;
}

.reminder-title-wrap h3 {
  margin: 0;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.reminder-subtext {
  font-size: 0.75rem;
  color: var(--text-secondary);
  display: block;
  margin-top: 2px;
}

.reminder-toggle-btn {
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-color);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.reminder-toggle-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(var(--primary-rgb), 0.35);
}

.reminder-body {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.reminder-time-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.reminder-time-row label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.reminder-time-input {
  background: var(--bg-color);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  font-size: 0.9rem;
  font-weight: 600;
  color-scheme: dark;
  outline: none;
  transition: border-color 0.2s ease;
}

.reminder-time-input:focus {
  border-color: var(--primary);
}

.reminder-presets {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.preset-btn {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  padding: 6px 4px;
  font-size: 0.7rem;
  font-weight: 500;
  cursor: pointer;
  text-align: center;
  transition: all 0.2s ease;
}

.preset-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
}

.preset-btn.selected {
  background: rgba(var(--primary-rgb), 0.15);
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 600;
}

.test-reminder-btn {
  background: transparent;
  border: 1px dashed var(--border-color);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  font-size: 0.75rem;
  cursor: pointer;
  transition: all 0.2s ease;
  width: 100%;
  text-align: center;
}

.test-reminder-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
}

/* --------------------------------------------------------------------------
   16. Rest Day Message
   -------------------------------------------------------------------------- */
.rest-day-message {
  margin: 40px 20px;
  text-align: center;
  padding: 40px 20px;
}

.rest-day-message .rest-icon {
  font-size: 3rem;
  margin-bottom: 12px;
  display: block;
}

.rest-day-message h2 {
  margin: 0 0 8px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
}

.rest-day-message p {
  margin: 0 auto;
  color: var(--text-secondary);
  font-size: 0.9rem;
  max-width: 280px;
  line-height: 1.5;
}

/* --------------------------------------------------------------------------
   17. Animations & Keyframes
   -------------------------------------------------------------------------- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}

@keyframes checkmark {
  0% {
    transform: scale(0);
  }
  50% {
    transform: scale(1.2);
  }
  100% {
    transform: scale(1);
  }
}

.exercise-card.just-completed .exercise-checkbox {
  animation: checkmark 0.4s ease;
}

.fade-in {
  animation: fadeInUp 0.3s ease;
}

/* --------------------------------------------------------------------------
   18. Notification Banner
   -------------------------------------------------------------------------- */
.notification-banner {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: var(--primary);
  color: #ffffff;
  padding: 12px 20px;
  text-align: center;
  font-size: 0.85rem;
  z-index: 200;
  transform: translateY(-100%);
  transition: transform 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
}

.notification-banner.visible {
  transform: translateY(0);
}

.notification-banner button {
  background: rgba(255, 255, 255, 0.2);
  border: none;
  color: #ffffff;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  margin-left: 12px;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 600;
  transition: background-color 0.2s ease;
}

.notification-banner button:hover {
  background: rgba(255, 255, 255, 0.3);
}

/* --------------------------------------------------------------------------
   19. Onboarding / Welcome Screen
   -------------------------------------------------------------------------- */
.onboarding-overlay {
  position: fixed;
  inset: 0;
  background: #1a1a2e;
  z-index: 500;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.onboarding-card {
  max-width: 400px;
  text-align: center;
  width: 100%;
}

.onboarding-card h1 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.onboarding-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 24px;
}

.onboarding-card .start-btn {
  background: var(--primary);
  color: #ffffff;
  border: none;
  padding: 14px 40px;
  border-radius: var(--radius-lg);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 4px 14px rgba(15, 155, 142, 0.4);
}

.onboarding-card .start-btn:hover {
  background: #12b3a4;
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(18, 179, 164, 0.45);
}

/* --------------------------------------------------------------------------
   20. Responsive Media Queries & iOS Safe Area Tweaks
   -------------------------------------------------------------------------- */
@media (min-width: 601px) {
  .app {
    border-left: 1px solid var(--border-color);
    border-right: 1px solid var(--border-color);
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.5);
  }

  .header h1 {
    font-size: 1.4rem;
  }

  .pain-checkin {
    margin: 20px;
    padding: 24px;
  }

  .exercise-card {
    margin: 12px 20px;
  }

  .stats-grid {
    gap: 16px;
  }

  .stat-card {
    padding: 20px;
  }

  .stat-value {
    font-size: 1.75rem;
  }
}

@supports (padding-bottom: env(safe-area-inset-bottom)) {
  .bottom-nav {
    padding-bottom: calc(8px + env(safe-area-inset-bottom));
  }
}