/* ========================================
   HabiTracker - Modern CSS Styles
   ======================================== */

/* CSS Variables - Design Tokens */
:root {
  /* Color Palette */
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --success: #10b981;
  --success-light: #34d399;
  --partial: #f59e0b;
  --partial-light: #fbbf24;
  --fail: #ef4444;
  --fail-light: #f87171;
  --empty: #9ca3af;
  
  /* Neutral Colors */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: rgba(30, 41, 59, 0.8);
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --border-color: rgba(148, 163, 184, 0.1);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.2);
  --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.3);
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* Reset & Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

/* Container */
.container {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

/* Utility */
.hidden {
  display: none !important;
}

/* ========================================
   Header Section
   ======================================== */
.app-header {
  text-align: center;
  margin-bottom: var(--spacing-lg);
  animation: fadeInDown 0.6s ease;
}

.logo-container {
  display: flex;
  justify-content: center;
  margin-bottom: var(--spacing-md);
}

.app-logo {
  height: 80px;
  width: auto;
  filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.3));
  transition: transform var(--transition-base);
}

.app-logo:hover {
  transform: scale(1.05);
}

.app-title {
  font-size: 3rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary) 0%, var(--success) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-xs);
  letter-spacing: -0.02em;
}

.app-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  font-weight: 300;
}

/* ========================================
   Tab Navigation
   ======================================== */
.tabs-nav {
  display: flex;
  gap: 0.5rem;
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 0.5rem;
  margin-bottom: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
  animation: fadeInDown 0.5s ease 0.1s both;
}

.tab-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  padding: 0.75rem 0.5rem;
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: 'Poppins', sans-serif;
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-base);
}

.tab-btn:hover {
  background: rgba(148, 163, 184, 0.08);
  color: var(--text-primary);
}

.tab-btn.active {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: white;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.tab-icon {
  font-size: 1.5rem;
}

.tab-label {
  font-size: 0.75rem;
  font-weight: 600;
}

/* ========================================
   View Sections
   ======================================== */
.view {
  animation: fadeInUp 0.4s ease both;
}

.view-header {
  margin-bottom: var(--spacing-lg);
  text-align: center;
}

.view-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

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

/* ========================================
   Daily Tracker / Register Section
   ======================================== */
.tracker-card {
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-xl);
}

.section-title {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.current-date {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

/* Date Picker */
.date-picker-group {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
  flex-wrap: wrap;
}

.date-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  white-space: nowrap;
}

.date-input {
  background: rgba(148, 163, 184, 0.08);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: 'Poppins', sans-serif;
  font-size: 0.9rem;
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  transition: border-color var(--transition-fast);
  flex: 1;
  min-width: 150px;
}

.date-input:focus {
  outline: none;
  border-color: var(--primary);
}

.date-input::-webkit-calendar-picker-indicator {
  filter: invert(1);
  cursor: pointer;
}

.checkbox-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.checkbox-label {
  display: flex;
  align-items: center;
  cursor: pointer;
  padding: var(--spacing-md);
  background: rgba(148, 163, 184, 0.05);
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  transition: all var(--transition-base);
}

.checkbox-label:hover {
  background: rgba(148, 163, 184, 0.1);
  border-color: var(--primary);
}

.custom-checkbox {
  appearance: none;
  width: 24px;
  height: 24px;
  border: 2px solid var(--text-secondary);
  border-radius: 6px;
  margin-right: var(--spacing-md);
  cursor: pointer;
  position: relative;
  transition: all var(--transition-base);
  flex-shrink: 0;
}

.custom-checkbox:checked {
  background: linear-gradient(135deg, var(--primary), var(--success));
  border-color: var(--success);
}

.custom-checkbox:checked::after {
  content: '✓';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: white;
  font-size: 14px;
  font-weight: bold;
}

.checkbox-text {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1rem;
  font-weight: 500;
}

.icon {
  font-size: 1.5rem;
}

.save-btn {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  font-family: 'Poppins', sans-serif;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-base);
}

.save-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 15px 25px rgba(99, 102, 241, 0.4);
}

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

.cancel-btn {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: rgba(148, 163, 184, 0.1);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 500;
  font-family: 'Poppins', sans-serif;
  cursor: pointer;
  transition: all var(--transition-base);
}

.cancel-btn:hover {
  background: rgba(148, 163, 184, 0.2);
  color: var(--text-primary);
}

.btn-icon {
  font-size: 1.25rem;
}

/* ========================================
   Calendar Section
   ======================================== */
.calendar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-lg);
  padding: 0 var(--spacing-sm);
}

.calendar-title {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: center;
  flex: 1;
}

.nav-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-base);
  color: var(--text-primary);
  font-size: 1.5rem;
  font-weight: 600;
}

.nav-btn:hover {
  background: var(--primary);
  border-color: var(--primary);
  transform: scale(1.05);
}

/* Calendar Grid */
.calendar-wrapper {
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-xl);
  margin-bottom: var(--spacing-lg);
}

.calendar-weekdays {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
}

.weekday {
  text-align: center;
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--text-secondary);
  padding: var(--spacing-xs);
}

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

.calendar-day {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  border: 2px solid transparent;
}

.calendar-day:not(.other-month):hover {
  transform: scale(1.12);
  z-index: 10;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.4);
}

.calendar-day.other-month {
  color: var(--empty);
  opacity: 0.35;
  background: rgba(148, 163, 184, 0.04);
}

.calendar-day.today {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.25);
}

/* Color Classes */
.calendar-day.success {
  background: linear-gradient(135deg, var(--success), var(--success-light));
  color: white;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.4);
}

.calendar-day.partial {
  background: linear-gradient(135deg, var(--partial), var(--partial-light));
  color: white;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

.calendar-day.fail {
  background: linear-gradient(135deg, var(--fail), var(--fail-light));
  color: white;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(239, 68, 68, 0.4);
}

.calendar-day.no-data {
  background: rgba(148, 163, 184, 0.1);
  color: var(--text-secondary);
}

/* ========================================
   Legend Section
   ======================================== */
.legend {
  background: var(--bg-card);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-lg);
  margin-bottom: var(--spacing-lg);
}

.legend-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.legend-items {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.legend-color {
  width: 22px;
  height: 22px;
  border-radius: 6px;
  flex-shrink: 0;
  box-shadow: var(--shadow-md);
}

.legend-color.success { background: linear-gradient(135deg, var(--success), var(--success-light)); }
.legend-color.partial { background: linear-gradient(135deg, var(--partial), var(--partial-light)); }
.legend-color.fail    { background: linear-gradient(135deg, var(--fail), var(--fail-light)); }
.legend-color.empty   { background: rgba(148, 163, 184, 0.1); border: 2px solid var(--empty); }

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

/* ========================================
   Edit Day Modal
   ======================================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: var(--spacing-md);
  animation: fadeIn 0.2s ease;
}

.modal-card {
  background: #1e293b;
  border: 1px solid rgba(148, 163, 184, 0.2);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg);
  width: 100%;
  max-width: 440px;
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.5);
  animation: slideUp 0.3s ease;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-xs);
}

.modal-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.modal-close {
  background: rgba(148, 163, 184, 0.1);
  border: none;
  border-radius: 50%;
  width: 36px;
  height: 36px;
  color: var(--text-secondary);
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: rgba(239, 68, 68, 0.2);
  color: var(--fail-light);
}

.modal-date {
  font-size: 0.9rem;
  color: var(--primary);
  font-weight: 500;
  margin-bottom: var(--spacing-md);
}

.modal-actions {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(30px) scale(0.97); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

/* ========================================
   Footer
   ======================================== */
.app-footer {
  text-align: center;
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.875rem;
  animation: fadeIn 0.6s ease 0.6s both;
}

.app-footer strong {
  color: var(--primary);
  font-weight: 600;
}

/* ========================================
   Toast Notification
   ======================================== */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border-color);
  opacity: 0;
  transform: translateY(100px);
  transition: all var(--transition-base);
  z-index: 3000;
  max-width: 300px;
  font-weight: 500;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

.toast.success { border-left: 4px solid var(--success); }
.toast.error   { border-left: 4px solid var(--fail); }

/* ========================================
   Animations
   ======================================== */
@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-30px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}

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

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
  .container { padding: var(--spacing-md); }
  .app-title { font-size: 2rem; }
  .app-logo  { height: 60px; }
  .calendar-title { font-size: 1.25rem; }
  .calendar-day { font-size: 0.75rem; }
  .toast { right: 1rem; bottom: 1rem; left: 1rem; max-width: none; }
  .tab-label { font-size: 0.7rem; }
  .tab-icon { font-size: 1.25rem; }
  .legend-items { gap: var(--spacing-sm); }
}

@media (max-width: 480px) {
  .app-title { font-size: 1.75rem; }
  .calendar-header { flex-wrap: wrap; gap: var(--spacing-sm); }
  .calendar-title { width: 100%; order: -1; margin-bottom: var(--spacing-sm); }
  .weekday { font-size: 0.7rem; }
  .tab-btn { padding: 0.6rem 0.25rem; }
  .date-picker-group { flex-direction: column; align-items: flex-start; }
}