/* ================================
   DESIGN SYSTEM & VARIABLES
   ================================ */

:root {
  /* Colors - Modern SaaS Palette */
  --color-primary: #3b82f6; /* Blue - Professional & trustworthy */
  --color-primary-light: #60a5fa; /* Light blue */
  --color-primary-dark: #1e40af; /* Dark blue */
  --color-secondary: #10b981; /* Emerald - Success & growth */
  --color-accent: #f59e0b; /* Amber - Highlights & CTAs */
  --color-success: #10b981; /* Success state */
  --color-danger: #ef4444; /* Red - Alerts & destructive */
  --color-warning: #f59e0b; /* Amber - Warnings */

  /* Neutrals - Professional */
  --color-bg: #f9fafb; /* Light gray background */
  --color-surface: #ffffff; /* White cards */
  --color-border: #e5e7eb; /* Gray border */
  --color-text: #111827; /* Near black text */
  --color-text-secondary: #6b7280; /* Gray text */
  --color-text-light: #9ca3af; /* Light gray text */

  /* Heat map colors - Professional gradient */
  --color-heat-0: #f3f4f6; /* Missed - neutral gray */
  --color-heat-1: #dbeafe; /* Light blue */
  --color-heat-2: #93c5fd; /* Medium blue */
  --color-heat-3: #3b82f6; /* Strong blue */

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;

  /* Typography */
  --font-family-sans:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-3xl: 2.5rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 200ms ease-in-out;
  --transition-slow: 300ms ease-in-out;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-full: 9999px;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #111827;
    --color-surface: #1f2937;
    --color-border: #374151;
    --color-text: #f3f4f6;
    --color-text-secondary: #d1d5db;
    --color-text-light: #9ca3af;
    --color-heat-0: #374151;
  }
}

/* ================================
   RESET & BASE STYLES
   ================================ */

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  letter-spacing: 0.3px;
}

/* ================================
   LAYOUT
   ================================ */

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-dark) 100%
  );
  color: white;
  padding: var(--spacing-xl) var(--spacing-lg);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-lg);
}

.header-content {
  flex: 1;
  min-width: 200px;
}

.app-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
  letter-spacing: -1px;
}

.app-subtitle {
  font-size: var(--font-size-sm);
  opacity: 0.9;
  font-weight: 300;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.date-display {
  font-size: var(--font-size-lg);
  font-weight: 600;
  text-align: right;
  min-width: 120px;
}

.header-btn {
  background: none;
  border: none;
  color: white;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm);
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
  width: 40px;
  height: 40px;
  opacity: 0.9;
}

.header-btn:hover {
  background-color: rgba(255, 255, 255, 0.1);
  opacity: 1;
}

.main-content {
  flex: 1;
  width: 70%;
  max-width: 900px;
  margin: 0 auto;
  padding: var(--spacing-xl) var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

/* Two-column layout */
.main-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  align-items: start;
}

/* Mobile: Stack to single column */
@media (max-width: 768px) {
  .main-layout {
    grid-template-columns: 1fr;
  }
}

/* ================================
   SECTIONS
   ================================ */

.section-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-lg);
  position: relative;
  padding-bottom: var(--spacing-sm);
  border-bottom: 2px solid var(--color-border);
}

/* Quote Section */
.quote-section {
  background: var(--color-surface);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.quote {
  font-style: normal;
  color: var(--color-text);
  text-align: center;
}

.quote p {
  font-size: var(--font-size-base);
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  line-height: 1.6;
  color: var(--color-text);
}

.quote footer {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-style: normal;
}

/* Habits Section */
.habits-section {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.add-habit-form {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

.input-field {
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: border-color var(--transition-base);
}

.input-field:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.habits-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.empty-state {
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-lg);
  color: var(--color-text-secondary);
  background-color: var(--color-surface);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--font-size-lg);
}

/* Habit Item */
.habit-item {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  transition: all var(--transition-base);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}
}

.habit-item:hover {
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
  border-color: var(--color-primary);
}

.habit-item.completed {
  background-color: rgba(59, 130, 246, 0.02);
  border-color: var(--color-success);
}

.habit-checkbox {
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  cursor: pointer;
  appearance: none;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: var(--color-bg);
  transition: all var(--transition-base);
  display: flex;
  align-items: center;
  justify-content: center;
}

.habit-checkbox:hover {
  border-color: var(--color-primary);
  background-color: rgba(59, 130, 246, 0.05);
}

.habit-checkbox:checked {
  background-color: var(--color-success);
  border-color: var(--color-success);
  position: relative;
}

.habit-checkbox:checked::after {
  content: "✓";
  color: white;
  font-weight: bold;
  font-size: 1.2rem;
  position: absolute;
}

.habit-content {
  flex: 1;
  min-width: 0;
}

.habit-name {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-xs);
  cursor: pointer;
  transition: color var(--transition-base);
}

.habit-name:hover {
  color: var(--color-primary);
}

.habit-time {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.habit-streak {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-primary);
  padding: var(--spacing-xs) var(--spacing-sm);
  background-color: rgba(59, 130, 246, 0.1);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  border: 1px solid rgba(59, 130, 246, 0.2);
}

.streak-icon {
  font-weight: bold;
  opacity: 0.7;
}

.habit-delete {
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  border: none;
  background-color: rgba(239, 68, 68, 0.08);
  color: var(--color-danger);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--font-size-base);
  transition: all var(--transition-base);
  display: flex;
  align-items: center;
  justify-content: center;
}
}

.habit-delete:hover {
  background-color: var(--color-danger);
  color: white;
}

/* Stats Section */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--spacing-lg);
}

.stat-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  text-align: center;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
  transition: all var(--transition-base);
}

.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.stat-value {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Monthly Section */
.monthly-section {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.monthly-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-md);
}

#monthDisplay {
  flex: 1;
  text-align: center;
  margin-bottom: 0;
}

.btn-nav {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--font-size-lg);
  font-weight: bold;
  transition: all var(--transition-base);
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-nav:hover {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}
  color: white;
}

.monthly-habit-selector {
  padding: var(--spacing-lg);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.heatmap-container {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
}

.heatmap-legend {
  display: flex;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  justify-content: center;
  flex-wrap: wrap;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.heat-cell {
  width: 1rem;
  height: 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

.heat-0 {
  background-color: var(--color-heat-0);
}
.heat-1 {
  background-color: var(--color-heat-1);
}
.heat-2 {
  background-color: var(--color-heat-2);
}
.heat-3 {
  background-color: var(--color-heat-3);
}

.heatmap {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: var(--spacing-sm);
}

.heatmap-day {
  aspect-ratio: 1;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-sm);
  font-weight: 600;
  cursor: pointer;
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
  background-color: var(--color-heat-0);
  color: var(--color-text-light);
  min-height: 50px;
  -webkit-box-align: center;
  -webkit-box-pack: center;
}

.heatmap-day:hover {
  transform: scale(1.1);
  box-shadow: var(--shadow-md);
}

.heatmap-day.heat-0 {
  background-color: var(--color-heat-0);
  color: var(--color-text-light);
}

.heatmap-day.heat-1 {
  background-color: var(--color-heat-1);
  color: var(--color-text);
}

.heatmap-day.heat-2 {
  background-color: var(--color-heat-2);
  color: white;
}

.heatmap-day.heat-3 {
  background-color: var(--color-heat-3);
  color: white;
}

.heatmap-label {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
}

/* Settings Section */
.settings-section {
  margin-top: var(--spacing-xl);
}

.settings-buttons {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

/* ================================
   BUTTONS
   ================================ */

.btn {
  padding: var(--spacing-md) var(--spacing-lg);
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-base);
  letter-spacing: 0.25px;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--color-primary);
  color: white;
  box-shadow: 0 1px 2px rgba(59, 130, 246, 0.2);
}

.btn-primary:hover {
  background-color: var(--color-primary-dark);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background-color: var(--color-accent);
  color: white;
  box-shadow: 0 1px 2px rgba(245, 158, 11, 0.2);
}

.btn-secondary:hover {
  background-color: #d97706;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.3);
  transform: translateY(-1px);
}

.btn-danger {
  background-color: var(--color-danger);
  color: white;
  box-shadow: 0 1px 2px rgba(239, 68, 68, 0.2);
}

.btn-danger:hover {
  background-color: #dc2626;
  box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3);
  transform: translateY(-1px);
}

/* ================================
   MODAL
   ================================ */

.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  animation: fadeIn var(--transition-base);
}

.modal.active {
  display: flex;
  align-items: center;
  justify-content: center;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.modal-content {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  max-width: 500px;
  width: 90%;
  max-height: 80vh;
  overflow-y: auto;
  animation: slideIn var(--transition-base);
}

.modal-content.modal-large {
  max-width: 700px;
}

@keyframes slideIn {
  from {
    transform: translateY(-50px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

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

.modal-header h3 {
  font-size: var(--font-size-xl);
  margin: 0;
}

.modal-close {
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  cursor: pointer;
  color: var(--color-text-secondary);
  transition: color var(--transition-base);
}

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

.modal-body {
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.modal-stat {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md);
  background-color: var(--color-bg);
  border-radius: var(--radius-sm);
}

.modal-stat-label {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
}

.modal-stat-value {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-primary);
}

/* Settings form sections */
.settings-form-section {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--color-border);
}

.settings-form-section:last-child {
  border-bottom: none;
}

.settings-subtitle {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.modal-footer {
  padding: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.modal-footer .btn {
  flex: 1;
  min-width: 120px;
}

/* ================================
   RESPONSIVE DESIGN
   ================================ */

/* TABLET: 768px and below */
@media (max-width: 1024px) {
  :root {
    --font-size-3xl: 2.2rem;
    --font-size-2xl: 1.75rem;
    --spacing-xl: 1.5rem;
    --spacing-2xl: 2.5rem;
  }

  .main-content {
    max-width: 100%;
    padding: var(--spacing-lg) var(--spacing-md);
  }

  .header {
    padding: var(--spacing-lg) var(--spacing-md);
  }

  .add-habit-form {
    grid-template-columns: 1fr 1fr auto;
  }

  .stats-grid {
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  }
}

/* TABLET: 768px and below */
@media (max-width: 768px) {
  :root {
    --font-size-3xl: 2rem;
    --font-size-2xl: 1.5rem;
    --font-size-xl: 1.25rem;
    --spacing-xl: 1.5rem;
    --spacing-2xl: 2rem;
  }

  html {
    font-size: 15px;
  }

  .header {
    flex-direction: row;
    text-align: left;
    padding: var(--spacing-lg) var(--spacing-md);
    gap: var(--spacing-md);
  }

  .header-content {
    min-width: auto;
    flex: 1;
  }

  .header-actions {
    gap: var(--spacing-sm);
  }

  .app-title {
    font-size: var(--font-size-2xl);
    margin-bottom: 0;
  }

  .app-subtitle {
    display: none;
  }

  .date-display {
    text-align: right;
    min-width: auto;
    font-size: var(--font-size-base);
  }

  .main-layout {
    grid-template-columns: 1fr;
  }
    font-size: var(--font-size-base);
  }

  .main-content {
    padding: var(--spacing-lg) var(--spacing-md);
    gap: var(--spacing-xl);
    max-width: 100%;
  }

  .quote-section {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
  }

  .quote p {
    font-size: var(--font-size-base);
    line-height: 1.6;
  }

  .quote footer {
    font-size: var(--font-size-sm);
  }

  .section-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
  }

  .add-habit-form {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
  }

  .add-habit-form input:nth-child(1) {
    grid-column: 1 / -1;
  }

  .add-habit-form input:nth-child(2) {
    grid-column: 1;
  }

  .add-habit-form button {
    grid-column: 2;
  }

  .input-field {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 16px;
  }

  .habit-item {
    flex-wrap: wrap;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
  }

  .habit-checkbox {
    width: 1.75rem;
    height: 1.75rem;
  }

  .habit-name {
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-xs);
  }

  .habit-time {
    font-size: var(--font-size-sm);
  }

  .habit-streak {
    font-size: var(--font-size-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
  }

  .habit-delete {
    width: 1.75rem;
    height: 1.75rem;
  }

  .stats-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
  }

  .stat-card {
    padding: var(--spacing-md);
  }

  .stat-value {
    font-size: var(--font-size-2xl);
  }

  .monthly-header {
    gap: var(--spacing-sm);
  }

  #monthDisplay {
    font-size: var(--font-size-lg);
  }

  .btn-nav {
    width: 2.2rem;
    height: 2.2rem;
    font-size: var(--font-size-base);
  }

  .heatmap-legend {
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    justify-content: center;
  }

  .legend-item {
    font-size: var(--font-size-xs, 0.75rem);
    gap: var(--spacing-xs);
  }

  .heat-cell {
    width: 0.875rem;
    height: 0.875rem;
  }

  .heatmap {
    grid-template-columns: repeat(7, 1fr);
    gap: var(--spacing-xs);
  }

  .heatmap-day {
    font-size: var(--font-size-xs, 0.75rem);
    aspect-ratio: 1;
  }

  .heatmap-label {
    font-size: var(--font-size-xs, 0.75rem);
  }

  .modal-content {
    width: 90%;
    max-height: 85vh;
  }

  .modal-header h3 {
    font-size: var(--font-size-lg);
  }

  .modal-stat {
    padding: var(--spacing-sm);
  }

  .modal-stat-label {
    font-size: var(--font-size-sm);
  }

  .modal-stat-value {
    font-size: var(--font-size-base);
  }

  .modal-footer {
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
  }

  .modal-footer .btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
    min-width: 100px;
  }

  .settings-buttons {
    flex-direction: column;
    gap: var(--spacing-sm);
  }

  .settings-buttons .btn {
    width: 100%;
    padding: var(--spacing-md);
  }

  .btn {
    font-size: var(--font-size-sm);
    padding: var(--spacing-sm) var(--spacing-md);
  }
}

/* MOBILE: 640px and below */
@media (max-width: 640px) {
  :root {
    --font-size-3xl: 1.75rem;
    --font-size-2xl: 1.25rem;
    --font-size-xl: 1.125rem;
    --font-size-lg: 1rem;
    --spacing-xl: 1rem;
    --spacing-2xl: 1.5rem;
    --spacing-lg: 1rem;
    --spacing-md: 0.75rem;
  }

  html {
    font-size: 14px;
  }

  * {
    -webkit-tap-highlight-color: transparent;
  }

  .header {
    padding: var(--spacing-md) var(--spacing-sm);
    gap: var(--spacing-sm);
  }

  .app-title {
    font-size: var(--font-size-xl);
  }

  .date-display {
    font-size: var(--font-size-sm);
  }

  .main-content {
    padding: var(--spacing-md);
    gap: var(--spacing-lg);
  }

  .quote-section {
    padding: var(--spacing-md);
    border-left-width: 3px;
    margin-bottom: var(--spacing-md);
  }

  .quote p {
    font-size: var(--font-size-sm);
    line-height: 1.5;
  }

  .section-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-xs);
  }

  .add-habit-form {
    grid-template-columns: 1fr;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
  }

  .add-habit-form input:nth-child(1),
  .add-habit-form input:nth-child(2),
  .add-habit-form button {
    grid-column: 1;
  }

  .input-field {
    padding: var(--spacing-sm);
    font-size: 16px;
    border-radius: var(--radius-sm);
  }

  .habit-item {
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
  }

  .habit-checkbox {
    width: 1.5rem;
    height: 1.5rem;
    min-width: 1.5rem;
  }

  .habit-content {
    flex: 0 1 100%;
    order: 2;
  }

  .habit-name {
    font-size: var(--font-size-base);
    margin-bottom: 0.25rem;
  }

  .habit-time {
    font-size: var(--font-size-xs, 0.75rem);
  }

  .habit-streak {
    order: 3;
    flex: 0 1 100%;
    font-size: var(--font-size-xs, 0.75rem);
    padding: var(--spacing-xs);
    margin-top: var(--spacing-xs);
  }

  .habit-delete {
    order: 1;
    width: 1.5rem;
    height: 1.5rem;
    font-size: var(--font-size-sm);
    margin-left: auto;
  }

  .empty-state {
    padding: var(--spacing-lg) var(--spacing-md);
    font-size: var(--font-size-base);
  }

  .stats-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
  }

  .stat-card {
    padding: var(--spacing-md);
  }

  .stat-value {
    font-size: var(--font-size-xl);
  }

  .stat-label {
    font-size: var(--font-size-xs, 0.75rem);
  }

  .monthly-habit-selector {
    padding: var(--spacing-md);
  }

  .monthly-header {
    gap: var(--spacing-xs);
  }

  #monthDisplay {
    font-size: var(--font-size-base);
  }

  .btn-nav {
    width: 2rem;
    height: 2rem;
    font-size: var(--font-size-sm);
    padding: 0;
  }

  .heatmap-container {
    padding: var(--spacing-md);
  }

  .heatmap-legend {
    flex-direction: column;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
    align-items: flex-start;
  }

  .legend-item {
    font-size: var(--font-size-xs, 0.75rem);
    gap: var(--spacing-xs);
  }

  .heat-cell {
    width: 0.75rem;
    height: 0.75rem;
  }

  .heatmap {
    grid-template-columns: repeat(7, 1fr);
    gap: 2px;
  }

  .heatmap-day {
    font-size: 0.65rem;
    aspect-ratio: 1;
    border-radius: 2px;
  }

  .heatmap-label {
    font-size: 0.65rem;
    padding: 0.25rem 0;
  }

  .modal {
    padding: var(--spacing-md);
  }

  .modal-content {
    width: 100%;
    max-width: 100%;
    max-height: 90vh;
    border-radius: var(--radius-md);
  }

  .modal-header {
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
  }

  .modal-header h3 {
    font-size: var(--font-size-base);
    flex: 1;
    word-break: break-word;
  }

  .modal-close {
    font-size: var(--font-size-lg);
    width: 1.5rem;
    height: 1.5rem;
    min-width: 1.5rem;
  }

  .modal-body {
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
  }

  .modal-stat {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
  }

  .modal-stat-value {
    font-size: var(--font-size-base);
  }

  .modal-footer {
    padding: var(--spacing-md);
    gap: var(--spacing-sm);
    flex-direction: column;
  }

  .modal-footer .btn {
    width: 100%;
    padding: var(--spacing-md);
    font-size: var(--font-size-sm);
  }

  .btn {
    font-size: var(--font-size-sm);
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
  }

  .btn-primary,
  .btn-secondary,
  .btn-danger {
    padding: var(--spacing-md) var(--spacing-lg);
  }

  .settings-buttons {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .settings-buttons .btn {
    width: 100%;
    padding: var(--spacing-md);
  }
}

/* SMALL MOBILE: 480px and below */
@media (max-width: 480px) {
  :root {
    --font-size-3xl: 1.5rem;
    --font-size-2xl: 1.125rem;
    --font-size-xl: 1rem;
    --font-size-lg: 0.875rem;
    --spacing-xl: 0.75rem;
    --spacing-2xl: 1.25rem;
  }

  html {
    font-size: 13px;
  }

  .app-title {
    font-size: var(--font-size-lg);
  }

  .header {
    padding: var(--spacing-sm);
  }

  .main-content {
    padding: var(--spacing-sm);
    gap: var(--spacing-md);
  }

  .quote-section {
    padding: var(--spacing-sm);
  }

  .quote p {
    font-size: var(--font-size-sm);
  }

  .quote footer {
    font-size: 0.7rem;
  }

  .section-title {
    font-size: var(--font-size-base);
  }

  .add-habit-form {
    padding: var(--spacing-sm);
    gap: var(--spacing-xs);
  }

  .input-field {
    padding: var(--spacing-sm);
    font-size: 16px;
  }

  .habit-item {
    padding: var(--spacing-sm);
    gap: var(--spacing-xs);
  }

  .habit-checkbox {
    width: 1.25rem;
    height: 1.25rem;
  }

  .habit-delete {
    width: 1.25rem;
    height: 1.25rem;
    font-size: 0.75rem;
  }

  .stats-grid {
    gap: var(--spacing-sm);
  }

  .stat-value {
    font-size: var(--font-size-lg);
  }

  .modal-header {
    padding: var(--spacing-sm);
  }

  .modal-body {
    padding: var(--spacing-sm);
  }

  .modal-footer {
    padding: var(--spacing-sm);
  }

  .monthly-header {
    gap: 0.25rem;
  }

  .btn-nav {
    width: 1.75rem;
    height: 1.75rem;
    font-size: 0.75rem;
  }

  .heatmap {
    gap: 1px;
  }

  .heatmap-day {
    font-size: 0.6rem;
  }
}

/* ================================
   TOUCH & MOBILE ENHANCEMENTS
   ================================ */

/* Improve touch targets for mobile */
@media (hover: none) and (pointer: coarse) {
  .btn,
  .habit-checkbox,
  .habit-delete,
  .btn-nav,
  button {
    min-height: 44px;
    min-width: 44px;
    padding: max(var(--spacing-md), calc(22px - 50%))
      max(var(--spacing-lg), calc(22px - 50%));
  }

  input[type="checkbox"],
  input[type="text"],
  input[type="time"],
  select {
    font-size: 16px;
  }

  .input-field:focus {
    box-shadow: 0 0 0 2px rgba(42, 157, 143, 0.2);
  }
}

/* Smooth scrolling for better mobile feel */
html {
  scroll-behavior: smooth;
}

/* Improve form inputs on mobile */
input,
select,
textarea {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}

select {
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 8px center;
  background-size: 1.2em;
  padding-right: 2.5rem;
}

/* Better button feedback on mobile */
.btn:active {
  transform: scale(0.98);
}

/* Prevent iOS text enlargement */
input,
select,
textarea {
  font-size: 16px;
}

/* ================================
   ACCESSIBILITY
   ================================ */

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }

  html {
    scroll-behavior: auto;
  }
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Ensure sufficient color contrast */
button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* ================================
   SMARTWATCH & VERY SMALL SCREENS
   ================================ */

/* Smartwatch screens (< 500px) */
@media (max-width: 500px) {
  :root {
    --font-size-sm: 0.75rem;
    --font-size-base: 0.875rem;
    --font-size-lg: 1rem;
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
  }

  .header {
    padding: var(--spacing-md) var(--spacing-sm);
    gap: var(--spacing-sm);
  }

  .app-title {
    font-size: 1.5rem;
  }

  .app-subtitle {
    font-size: 0.65rem;
  }

  .main-content {
    width: 90%;
    max-width: 100%;
    padding: var(--spacing-md);
  }

  .quote-section {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
  }

  .quote p {
    font-size: 0.75rem;
  }

  .quote footer {
    font-size: 0.65rem;
  }

  .section-title {
    font-size: 1rem;
    margin-bottom: var(--spacing-md);
  }

  .habits-section {
    gap: var(--spacing-md);
  }

  .habit-item {
    padding: var(--spacing-sm);
  }

  .habit-checkbox {
    width: 1.25rem;
    height: 1.25rem;
  }

  .habit-name {
    font-size: 0.7rem;
  }

  .heatmap-day {
    min-height: 40px;
    font-size: 0.75rem;
  }

  .heatmap {
    gap: var(--spacing-xs);
  }

  .stat-value {
    font-size: 1.5rem;
  }

  .stat-label {
    font-size: 0.6rem;
  }

  .btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.75rem;
  }

  .header-btn {
    width: 36px;
    height: 36px;
  }

  .modal-content {
    width: 95vw;
    max-height: 90vh;
  }

  .input-field {
    font-size: 0.75rem;
    padding: var(--spacing-sm);
  }

  .add-habit-form {
    grid-template-columns: 1fr;
    gap: var(--spacing-sm);
  }
}

/* Circular smartwatch screens (< 350px) */
@media (max-width: 350px) {
  .header {
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: var(--spacing-sm);
  }

  .app-title {
    font-size: 1.25rem;
    margin-bottom: 0;
  }

  .app-subtitle {
    display: none;
  }

  .header-actions {
    flex-direction: column;
    gap: var(--spacing-xs);
    width: 100%;
  }

  .date-display {
    min-width: auto;
    text-align: center;
  }

  .main-content {
    width: 95%;
    padding: var(--spacing-sm);
  }

  .section-title {
    font-size: 0.9rem;
    text-align: center;
  }

  .heatmap-day {
    min-height: 35px;
    font-size: 0.65rem;
  }

  .heatmap-label {
    font-size: 0.6rem;
  }

  .quote p {
    font-size: 0.65rem;
  }

  .stat-card {
    padding: var(--spacing-sm);
  }

  .stat-value {
    font-size: 1.25rem;
  }

  .btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.65rem;
  }

  .modal-content {
    width: 98vw;
    max-height: 85vh;
    border-radius: 50%;
  }
}

@media print {
  .add-habit-form,
  .settings-section,
  .modal {
    display: none;
  }

  .main-content {
    gap: var(--spacing-lg);
  }
}