/* =====================================================
   InnoCards – Styles (I4S Branding)
   ===================================================== */

:root {
  /* I4S Brand Colors */
  --color-primary: #474747;
  --color-secondary: #F9891D;
  --color-accent: #5E3735;

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

  /* Typography */
  --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.25rem;
  --font-size-xl: 1.5rem;
  --font-size-xxl: 2rem;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.15);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.18);

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;

  /* Light theme (default) */
  --bg-body: #f5f5f5;
  --bg-card: #ffffff;
  --bg-header: var(--color-primary);
  --bg-footer: var(--color-primary);
  --text-primary: var(--color-primary);
  --text-secondary: #666666;
  --text-on-dark: #ffffff;
  --border-color: #e0e0e0;
  --input-bg: #ffffff;
  --hover-bg: #f0f0f0;
}

/* Dark theme */
[data-theme="dark"] {
  --bg-body: #1a1a1a;
  --bg-card: #2d2d2d;
  --bg-header: var(--color-primary);
  --bg-footer: var(--color-primary);
  --text-primary: #e0e0e0;
  --text-secondary: #aaaaaa;
  --text-on-dark: #ffffff;
  --border-color: #444444;
  --input-bg: #3a3a3a;
  --hover-bg: #3a3a3a;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

/* =====================================================
   Focus Styles
   ===================================================== */
:focus-visible {
  outline: 3px solid var(--color-secondary);
  outline-offset: 2px;
}

a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible, select:focus-visible {
  outline: 3px solid var(--color-secondary);
  outline-offset: 2px;
}

/* =====================================================
   Header
   ===================================================== */
.app-header {
  background: var(--bg-header);
  color: var(--text-on-dark);
  padding: var(--space-md) var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-md);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}

.app-header__logo {
  height: 40px;
  width: auto;
  flex-shrink: 0;
}

.app-header__title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--text-on-dark);
  text-decoration: none;
  white-space: nowrap;
}

.app-header__title:hover {
  color: var(--color-secondary);
}

.app-header__nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* =====================================================
   Main Content
   ===================================================== */
.app-main {
  flex: 1;
  padding: var(--space-xl) var(--space-lg);
  max-width: 900px;
  width: 100%;
  margin: 0 auto;
}

/* =====================================================
   Footer
   ===================================================== */
.app-footer {
  background: var(--bg-footer);
  color: var(--text-on-dark);
  padding: var(--space-lg);
  text-align: center;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: var(--space-md);
}

.app-footer a {
  color: var(--color-secondary);
  text-decoration: none;
}

.app-footer a:hover {
  text-decoration: underline;
}

.app-footer__copy {
  font-size: var(--font-size-sm);
}

/* =====================================================
   Buttons
   ===================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--font-size-md);
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
  text-decoration: none;
  line-height: 1.4;
  white-space: nowrap;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

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

.btn--primary {
  background: var(--color-secondary);
  color: #1a1a1a;
}
.btn--primary:hover {
  background: #e67a18;
}

.btn--secondary {
  background: var(--color-accent);
  color: #ffffff;
}
.btn--secondary:hover {
  background: #4a2c2b;
}

.btn--outline {
  background: transparent;
  color: var(--text-primary);
  border: 2px solid var(--border-color);
}
.btn--outline:hover {
  border-color: var(--color-secondary);
  color: var(--color-secondary);
}

.btn--danger {
  background: #d32f2f;
  color: #ffffff;
}
.btn--danger:hover {
  background: #b71c1c;
}

.btn--sm {
  padding: var(--space-xs) var(--space-sm);
  font-size: var(--font-size-sm);
}

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

.form-label {
  display: block;
  font-weight: 600;
  margin-bottom: var(--space-xs);
  color: var(--text-primary);
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: var(--font-size-md);
  font-family: var(--font-family);
  background: var(--input-bg);
  color: var(--text-primary);
  transition: border-color var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  border-color: var(--color-secondary);
  outline: none;
  box-shadow: 0 0 0 3px rgba(249, 137, 29, 0.25);
}

.form-textarea {
  min-height: 100px;
  resize: vertical;
}

.form-hint {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-top: var(--space-xs);
}

/* =====================================================
   Cards / Panels
   ===================================================== */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--space-lg);
  margin-bottom: var(--space-md);
  transition: box-shadow var(--transition-fast);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

/* =====================================================
   Welcome Screen
   ===================================================== */
.welcome-screen {
  text-align: center;
  padding: var(--space-xxl) var(--space-lg);
}

.welcome-screen__logo {
  max-width: 120px;
  height: auto;
  margin-bottom: var(--space-xl);
}

.welcome-screen__title {
  font-size: var(--font-size-xxl);
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
}

.welcome-screen__text {
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

/* =====================================================
   Profile List
   ===================================================== */
.profile-list {
  display: grid;
  gap: var(--space-md);
  max-width: 500px;
  margin: 0 auto;
}

.profile-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  box-shadow: var(--shadow-sm);
}

.profile-item__name {
  font-weight: 600;
  color: var(--text-primary);
}

.profile-item__actions {
  display: flex;
  gap: var(--space-xs);
}

/* =====================================================
   Dashboard
   ===================================================== */
.dashboard-greeting {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-lg);
  color: var(--color-primary);
}

.dashboard-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.stat-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  text-align: center;
  box-shadow: var(--shadow-sm);
}

.stat-card__value {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-secondary);
}

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

/* =====================================================
   Search / Filter Bar
   ===================================================== */
.search-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  align-items: center;
}

.search-bar__input {
  flex: 1;
  min-width: 200px;
}

.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.chip {
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-full);
  font-size: var(--font-size-sm);
  cursor: pointer;
  border: 2px solid var(--border-color);
  background: transparent;
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.chip--active {
  background: var(--color-accent);
  color: #ffffff;
  border-color: var(--color-accent);
}

/* =====================================================
   Deck Cards
   ===================================================== */
.deck-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.deck-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

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

.deck-card__title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-primary);
}

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

.deck-card__count {
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
  font-weight: 600;
}

.deck-card__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-md);
}

/* =====================================================
   Flashcard List
   ===================================================== */
.flashcard-item {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  margin-bottom: var(--space-md);
  box-shadow: var(--shadow-sm);
}

.flashcard-item__front {
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--space-xs);
}

.flashcard-item__back {
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
}

.flashcard-item__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.tag {
  background: var(--color-accent);
  color: #ffffff;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
}

.flashcard-item__actions {
  display: flex;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

/* =====================================================
   Study Mode
   ===================================================== */
.study-container {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.study-progress {
  margin-bottom: var(--space-lg);
}

.study-progress__bar {
  width: 100%;
  height: 8px;
  background: var(--border-color);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: var(--space-sm);
}

.study-progress__fill {
  height: 100%;
  background: var(--color-secondary);
  border-radius: var(--radius-full);
  transition: width var(--transition-normal);
}

.study-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-lg);
  box-shadow: var(--shadow-md);
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-lg);
  user-select: none;
}

.study-card__question,
.study-card__answer {
  width: 100%;
}

.study-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-sm);
}

/* =====================================================
   Modal / Dialog Overlay
   ===================================================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: var(--space-lg);
}

.modal {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  max-width: 500px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
}

.modal__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-lg);
  color: var(--color-primary);
}

.modal__actions {
  display: flex;
  gap: var(--space-sm);
  justify-content: flex-end;
  margin-top: var(--space-lg);
}

/* =====================================================
   Toast Notifications
   ===================================================== */
.toast-container {
  position: fixed;
  bottom: var(--space-lg);
  left: 50%;
  transform: translateX(-50%);
  z-index: 300;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.toast {
  background: var(--color-primary);
  color: #ffffff;
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  opacity: 0.95;
  font-size: var(--font-size-sm);
}

/* =====================================================
   Empty State
   ===================================================== */
.empty-state {
  text-align: center;
  padding: var(--space-xxl) var(--space-lg);
  color: var(--text-secondary);
}

/* =====================================================
   Install Banner
   ===================================================== */
.install-banner {
  background: var(--bg-card);
  border: 2px solid var(--color-secondary);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  text-align: center;
  margin-bottom: var(--space-lg);
}

/* =====================================================
   Data Notice
   ===================================================== */
.data-notice {
  background: var(--bg-card);
  border-left: 4px solid var(--color-secondary);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
}

/* =====================================================
   Advertising Banner
   ===================================================== */
.ad-banner {
  text-align: center;
  padding: var(--space-sm);
}

.ad-banner__label {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
}

.ad-banner__link img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
}

/* =====================================================
   Page Sections (Show/Hide)
   ===================================================== */
.page-section {
  display: none;
}

.page-section.active {
  display: block;
}

/* =====================================================
   Legal Pages
   ===================================================== */
.legal-content {
  max-width: 700px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

.legal-content h1 {
  color: var(--color-primary);
  margin-bottom: var(--space-lg);
}

.legal-content p {
  margin-bottom: var(--space-md);
  line-height: 1.7;
}

/* =====================================================
   Responsive
   ===================================================== */
@media (max-width: 600px) {
  .app-header {
    padding: var(--space-sm) var(--space-md);
  }
  .app-header__title {
    font-size: var(--font-size-md);
  }
  .app-main {
    padding: var(--space-md);
  }
  .dashboard-actions {
    flex-direction: column;
  }
  .dashboard-actions .btn {
    width: 100%;
    text-align: center;
  }
}

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

/* =====================================================
   Back link (shared across inner pages)
   ===================================================== */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--color-secondary);
  text-decoration: none;
  font-weight: 600;
  margin-bottom: var(--space-lg);
}
.back-link:hover {
  text-decoration: underline;
}

/* Section heading */
.section-title {
  font-size: var(--font-size-xl);
  color: var(--color-primary);
  margin-bottom: var(--space-lg);
}