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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: linear-gradient(135deg, #0f0f23 0%, #1a1a2e 50%, #16213e 100%);
  min-height: 100vh;
  color: #ffffff;
  overflow-x: hidden;
}

/* Background Pattern */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    radial-gradient(circle at 25% 25%, rgba(120, 119, 198, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 75% 75%, rgba(255, 107, 107, 0.1) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

/* App Container */
.app-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

/* Main Card */
.habit-card {
  background: rgba(28, 28, 42, 0.95);
  backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 24px;
  padding: 32px;
  width: 100%;
  max-width: 480px;
  box-shadow: 
    0 32px 64px rgba(0, 0, 0, 0.4),
    0 16px 32px rgba(0, 0, 0, 0.2),
    inset 0 1px 0 rgba(255, 255, 255, 0.1);
  position: relative;
  overflow: hidden;
}

.habit-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 32px;
  position: relative;
}

.back-btn {
  position: absolute;
  top: -8px;
  left: -8px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  color: #ffffff;
  cursor: pointer;
  padding: 12px;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.back-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.header-content h1 {
  font-size: 2.2rem;
  font-weight: 700;
  background: linear-gradient(135deg, #ff6b6b, #ffd93d, #6bcf7f);
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.fire-icon {
  font-size: 2rem;
  filter: drop-shadow(0 0 10px rgba(255, 107, 107, 0.3));
  animation: flicker 2s ease-in-out infinite alternate;
}

@keyframes flicker {
  0% { transform: scale(1); }
  100% { transform: scale(1.1); }
}

.subtitle {
  font-size: 1rem;
  color: rgba(255, 255, 255, 0.7);
  font-weight: 400;
}

/* Stats Section */
.stats-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 32px;
}

.stat-card {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 16px;
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.stat-card:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.stat-icon {
  font-size: 1.5rem;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 10px;
}

.stat-content {
  display: flex;
  flex-direction: column;
}

.stat-number {
  font-size: 1.8rem;
  font-weight: 700;
  color: #ffffff;
  line-height: 1;
}

.stat-label {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
  font-weight: 500;
}

/* Input Section */
.habit-input-section {
  margin-bottom: 32px;
}

.input-group {
  display: flex;
  gap: 12px;
  position: relative;
}

#habit-input {
  flex: 1;
  background: rgba(255, 255, 255, 0.08);
  border: 2px solid rgba(255, 255, 255, 0.1);
  border-radius: 16px;
  padding: 16px 20px;
  color: #ffffff;
  font-size: 1rem;
  font-weight: 400;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

#habit-input::placeholder {
  color: rgba(255, 255, 255, 0.5);
}

#habit-input:focus {
  outline: none;
  border-color: rgba(107, 203, 119, 0.5);
  background: rgba(255, 255, 255, 0.12);
  box-shadow: 0 0 0 4px rgba(107, 203, 119, 0.1);
}

.add-btn {
  background: linear-gradient(135deg, #6bcf7f, #4dabf7);
  border: none;
  border-radius: 16px;
  padding: 16px;
  color: white;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(107, 203, 119, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
}

.add-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(107, 203, 119, 0.4);
}

.add-btn:active {
  transform: scale(0.95);
}

/* Habits Section */
.habits-section {
  margin-bottom: 32px;
}

.section-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.habit-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.habit-item {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  padding: 10px 14px;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
  font-size: 0.9rem;
}

.habit-item:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-1px);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.habit-item.completed {
  background: rgba(107, 203, 119, 0.1);
  border-color: rgba(107, 203, 119, 0.3);
}

.habit-checkbox {
  width: 24px;
  height: 24px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-radius: 8px;
  background: transparent;
  cursor: pointer;
  position: relative;
  transition: all 0.3s ease;
  appearance: none;
  flex-shrink: 0;
}

.habit-checkbox:checked {
  background: linear-gradient(135deg, #6bcf7f, #4dabf7);
  border-color: #6bcf7f;
}

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

.habit-text {
  flex: 1;
  font-size: 1rem;
  font-weight: 500;
  color: #ffffff;
  transition: all 0.3s ease;
}

.habit-item.completed .habit-text {
  color: rgba(255, 255, 255, 0.7);
  text-decoration: line-through;
}

.delete-btn {
  background: rgba(255, 107, 107, 0.2);
  border: 1px solid rgba(255, 107, 107, 0.3);
  border-radius: 10px;
  padding: 8px;
  color: #ff6b6b;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0.7;
}

.delete-btn:hover {
  background: rgba(255, 107, 107, 0.3);
  opacity: 1;
  transform: scale(1.1);
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 40px 20px;
  color: rgba(255, 255, 255, 0.5);
}

.empty-state.hidden {
  display: none;
}

.empty-icon {
  font-size: 3rem;
  margin-bottom: 16px;
  opacity: 0.6;
}

.empty-state p {
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 8px;
}

.empty-state span {
  font-size: 0.9rem;
  opacity: 0.8;
}

/* Done Today Button */
.done-today-btn {
  width: 100%;
  background: linear-gradient(135deg, #6bcf7f, #4dabf7);
  border: none;
  border-radius: 16px;
  padding: 18px 24px;
  color: white;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  box-shadow: 0 8px 25px rgba(107, 203, 119, 0.3);
  margin-bottom: 24px;
}

.done-today-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 35px rgba(107, 203, 119, 0.4);
}

.done-today-btn:active {
  transform: translateY(-1px);
}

.done-today-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

.btn-icon {
  font-size: 1.2rem;
}

/* Messages */
.message {
  border-radius: 16px;
  padding: 16px 20px;
  margin-top: 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  animation: slideIn 0.4s ease-out;
  backdrop-filter: blur(10px);
}

.message.hidden {
  display: none;
}

.message-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
}

.message-content {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.message-content strong {
  font-weight: 600;
  font-size: 0.95rem;
}

.message-content span {
  font-size: 0.9rem;
  opacity: 0.9;
}

.message.success {
  background: rgba(107, 203, 119, 0.15);
  border: 1px solid rgba(107, 203, 119, 0.3);
  color: #6bcf7f;
}

.message.warning {
  background: rgba(255, 211, 61, 0.15);
  border: 1px solid rgba(255, 211, 61, 0.3);
  color: #ffd93d;
}

.message.error {
  background: rgba(255, 107, 107, 0.15);
  border: 1px solid rgba(255, 107, 107, 0.3);
  color: #ff6b6b;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Design */
@media (max-width: 640px) {
  .app-container {
    padding: 12px;
  }

  .habit-card {
    padding: 24px;
  }

  .header-content h1 {
    font-size: 1.8rem;
  }

  .stats-section {
    gap: 12px;
  }

  .stat-card {
    padding: 16px;
  }

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

  .input-group {
    flex-direction: column;
    gap: 12px;
  }

  .add-btn {
    padding: 16px;
    align-self: stretch;
  }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* Focus styles for keyboard navigation */
button:focus-visible,
input:focus-visible {
  outline: 2px solid #6bcf7f;
  outline-offset: 2px;
}