/**
 * Acorn Activity Tracker Styles
 * Mobile-first, responsive design
 */

/* ===== CSS Variables ===== */
:root {
  /* Colors - Light Mode */
  --color-primary: #4CAF50;
  --color-primary-dark: #388E3C;
  --color-secondary: #2196F3;
  --color-success: #4CAF50;
  --color-warning: #FF9800;
  --color-danger: #F44336;
  
  --color-bg: #ffffff;
  --color-bg-secondary: #f5f5f5;
  --color-surface: #ffffff;
  --color-text: #212121;
  --color-text-secondary: #757575;
  --color-border: #e0e0e0;
  --color-shadow: rgba(0, 0, 0, 0.1);
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
  
  /* Z-index */
  --z-dropdown: 1000;
  --z-modal: 1100;
  --z-toast: 1200;
}

/* Dark Mode */
[data-theme="dark"] {
  --color-bg: #121212;
  --color-bg-secondary: #1e1e1e;
  --color-surface: #2c2c2c;
  --color-text: #e0e0e0;
  --color-text-secondary: #a0a0a0;
  --color-border: #3c3c3c;
  --color-shadow: rgba(0, 0, 0, 0.3);
}

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

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-base), color var(--transition-base);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }

p {
  margin-bottom: var(--spacing-md);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

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

/* ===== Header ===== */
.app-header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.logo-icon {
  font-size: var(--font-size-2xl);
}

.logo-text {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-primary);
  margin: 0;
}

.header-nav {
  display: flex;
  gap: var(--spacing-sm);
}

/* ===== Main Content ===== */
.app-main {
  flex: 1;
  padding: var(--spacing-xl) 0;
}

/* ===== Welcome Section ===== */
.welcome {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  padding: var(--spacing-xl);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  border-radius: var(--radius-lg);
  color: white;
}

.welcome h2 {
  color: white;
  margin-bottom: var(--spacing-sm);
}

.welcome p {
  color: rgba(255, 255, 255, 0.9);
  margin: 0;
}

/* ===== Sections ===== */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
}

.section-title {
  margin: 0;
}

/* ===== Habits Grid ===== */
.habits-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

/* ===== Habit Card ===== */
.habit-card {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  border-left: 4px solid var(--color-primary);
}

.habit-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.habit-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--spacing-md);
}

.habit-icon {
  font-size: var(--font-size-2xl);
}

.habit-actions {
  display: flex;
  gap: var(--spacing-xs);
}

.habit-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.habit-description {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  margin-bottom: var(--spacing-md);
}

.habit-stats {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
}

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

.habit-streak strong {
  color: var(--color-primary);
  font-size: var(--font-size-lg);
}

/* ===== Empty State ===== */
.empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--spacing-2xl);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  border: 2px dashed var(--color-border);
}

.empty-icon {
  font-size: 4rem;
  margin-bottom: var(--spacing-md);
}

.empty-state h3 {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.empty-state p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-weight: 500;
  line-height: 1.5;
  text-align: center;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover:not(:disabled) {
  background-color: var(--color-border);
}

.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  font-size: var(--font-size-lg);
  background-color: transparent;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.btn-icon:hover {
  background-color: var(--color-bg-secondary);
}

/* ===== Modal ===== */
.modal {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal);
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md);
}

.modal[aria-hidden="false"] {
  display: flex;
}

.modal-overlay {
  position: absolute;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
}

.modal-content {
  position: relative;
  width: 100%;
  max-width: 500px;
  max-height: 90vh;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

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

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

.modal-close {
  font-size: var(--font-size-xl);
}

.modal-body {
  padding: var(--spacing-lg);
  overflow-y: auto;
}

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

/* ===== Forms ===== */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  color: var(--color-text);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-base);
  font-family: inherit;
  color: var(--color-text);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
}

.form-row {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
}

.form-row .form-group {
  flex: 1;
  margin-bottom: 0;
}

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

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

.settings-section h3 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-md);
}

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

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: var(--spacing-lg);
  left: 50%;
  transform: translateX(-50%) translateY(200%);
  z-index: var(--z-toast);
  min-width: 300px;
  max-width: 500px;
  padding: var(--spacing-md) var(--spacing-lg);
  background-color: var(--color-text);
  color: var(--color-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  transition: transform var(--transition-base);
}

.toast.show {
  transform: translateX(-50%) translateY(0);
}

.toast-message {
  font-size: var(--font-size-base);
}

/* ===== Footer ===== */
.app-footer {
  padding: var(--spacing-xl) 0;
  text-align: center;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .habits-grid {
    grid-template-columns: 1fr;
  }
  
  .section-header {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-md);
  }
  
  .welcome {
    padding: var(--spacing-lg);
  }
  
  .form-row {
    flex-direction: column;
  }
  
  .form-row .form-group {
    width: 100%;
  }
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}