/* DeepTrace — Modern UI Design System */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 10000;
  padding: 0.75rem 1.5rem;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 0.9375rem;
  text-decoration: none;
  border-radius: 0 0 var(--radius-md) var(--radius-md);
}

.skip-link:focus {
  top: 0;
  outline: 3px solid var(--text-primary);
  outline-offset: 2px;
}

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

/* ===== Light Theme (Default) ===== */
:root {
  /* Neutral palette */
  --neutral-50: #fafafa;
  --neutral-100: #f5f5f5;
  --neutral-200: #e5e5e5;
  --neutral-300: #d4d4d4;
  --neutral-400: #a3a3a3;
  --neutral-500: #737373;
  --neutral-600: #525252;
  --neutral-700: #404040;
  --neutral-800: #262626;
  --neutral-900: #171717;

  /* Brand colors */
  --primary-50: #eff6ff;
  --primary-100: #dbeafe;
  --primary-200: #bfdbfe;
  --primary-500: #3b82f6;
  --primary-600: #2563eb;
  --primary-700: #1d4ed8;

  /* Semantic colors */
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  --info: #3b82f6;

  /* Application colors */
  --bg-primary: #ffffff;
  --bg-secondary: #fafafa;
  --bg-tertiary: #f5f5f5;
  --text-primary: #171717;
  --text-secondary: #525252;
  --text-tertiary: #a3a3a3;
  --border-primary: #e5e5e5;
  --border-secondary: #d4d4d4;
  --accent: var(--primary-500);
  --accent-hover: var(--primary-600);

  /* Spacing */
  --sidebar-width: 260px;
  --topbar-height: 64px;

  /* Typography */
  --font-base: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', monospace;

  /* Shadows */
  --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
}

/* ===== Dark Theme ===== */
[data-theme="dark"] {
  --neutral-50: #171717;
  --neutral-100: #262626;
  --neutral-200: #404040;
  --neutral-300: #525252;
  --neutral-400: #737373;
  --neutral-500: #a3a3a3;
  --neutral-600: #d4d4d4;
  --neutral-700: #e5e5e5;
  --neutral-800: #f5f5f5;
  --neutral-900: #fafafa;

  --primary-50: #172554;
  --primary-100: #1e3a8a;
  --primary-200: #1e40af;
  --primary-500: #3b82f6;
  --primary-600: #60a5fa;
  --primary-700: #93c5fd;

  --bg-primary: #0a0a0a;
  --bg-secondary: #171717;
  --bg-tertiary: #262626;
  --text-primary: #fafafa;
  --text-secondary: #a3a3a3;
  --text-tertiary: #525252;
  --border-primary: #262626;
  --border-secondary: #404040;
  --accent: var(--primary-600);
  --accent-hover: var(--primary-500);

  --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.4);
  --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.5), 0 1px 2px -1px rgb(0 0 0 / 0.5);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.5), 0 2px 4px -2px rgb(0 0 0 / 0.5);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.6), 0 4px 6px -4px rgb(0 0 0 / 0.6);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.6), 0 8px 10px -6px rgb(0 0 0 / 0.6);
}

/* ===== Base Styles ===== */
html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-base);
  background: var(--bg-secondary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.2s ease, color 0.2s ease;
}

/* ===== Layout ===== */
.app-container {
  display: flex;
  min-height: 100vh;
  background: var(--bg-secondary);
}

/* ===== Sidebar ===== */
.sidebar {
  width: var(--sidebar-width);
  background: var(--bg-primary);
  border-right: 1px solid var(--border-primary);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 100;
}

.sidebar-header {
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-primary);
}

.sidebar-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.sidebar-logo-accent {
  color: var(--accent);
}

.case-badge {
  margin-top: 0.75rem;
  padding: 0.5rem 0.75rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.case-badge-icon {
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 50%;
}

.sidebar-nav {
  flex: 1;
  padding: 1rem;
  overflow-y: auto;
}

.nav-section {
  margin-bottom: 1.5rem;
}

.nav-section-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  padding: 0 0.75rem;
  margin-bottom: 0.5rem;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 0.75rem;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9375rem;
  font-weight: 500;
  transition: all 0.15s ease;
  margin-bottom: 0.25rem;
}

.nav-item:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.nav-item.active {
  background: var(--accent);
  color: white;
}

.nav-item-icon {
  font-size: 1.125rem;
  width: 1.25rem;
  text-align: center;
}

.sidebar-footer {
  padding: 1rem;
  border-top: 1px solid var(--border-primary);
}

.theme-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 0.75rem;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 0.9375rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.theme-toggle:hover {
  background: var(--bg-tertiary);
  border-color: var(--border-secondary);
  color: var(--text-primary);
}

.theme-icon {
  font-size: 1.125rem;
}

.icon-light { display: none; }
.icon-dark { display: inline; }
[data-theme="dark"] .icon-light { display: inline; }
[data-theme="dark"] .icon-dark { display: none; }

/* ===== Main Content ===== */
.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
}

.content-header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-primary);
  padding: 1.5rem 2rem;
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(8px);
}

.content-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.content-subtitle {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.content-body {
  padding: 2rem;
}

/* ===== Cards ===== */
.card {
  background: var(--bg-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all 0.2s ease;
}

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

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.card-body {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* ===== Stats Grid ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all 0.2s ease;
}

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

.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1;
}

.stat-value-accent {
  color: var(--accent);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s ease;
  border: none;
  font-family: var(--font-base);
}

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

.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: var(--shadow-sm);
}

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

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

/* ===== Forms ===== */
.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: 0.625rem 0.875rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.9375rem;
  font-family: var(--font-base);
  transition: all 0.15s ease;
}

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

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

/* ===== Case Selector ===== */
.selector-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  padding: 2rem;
}

.selector-card {
  width: 100%;
  max-width: 600px;
  background: var(--bg-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-xl);
  padding: 3rem;
  box-shadow: var(--shadow-xl);
}

.selector-header {
  text-align: center;
  margin-bottom: 3rem;
}

.selector-logo {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.selector-subtitle {
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

.case-list {
  margin-bottom: 2rem;
}

.case-list-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: 1rem;
}

.case-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
  text-decoration: none;
  transition: all 0.15s ease;
}

.case-item:hover {
  background: var(--bg-primary);
  border-color: var(--accent);
  box-shadow: var(--shadow-sm);
}

.case-item-name {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-primary);
}

.case-item-arrow {
  color: var(--text-tertiary);
  transition: all 0.15s ease;
}

.case-item:hover .case-item-arrow {
  color: var(--accent);
  transform: translateX(4px);
}

.divider {
  display: flex;
  align-items: center;
  margin: 2rem 0;
}

.divider::before,
.divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border-primary);
}

.divider span {
  padding: 0 1rem;
  font-size: 0.875rem;
  color: var(--text-tertiary);
  font-weight: 500;
}

/* ===== Utilities ===== */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 2rem; }

/* ===== Animations ===== */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-in {
  animation: fadeIn 0.3s ease;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border-secondary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-tertiary);
}

/* ===== Global Focus Indicators (WCAG 2.4.7 / 2.4.13 AAA) ===== */

:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.btn:focus-visible,
.nav-item:focus-visible,
.card:focus-visible,
.case-item:focus-visible,
.theme-toggle:focus-visible,
.font-size-btn:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
  box-shadow: 0 0 0 5px rgba(59, 130, 246, 0.15);
}

.form-input:focus-visible,
.form-textarea:focus-visible,
.form-select:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 0;
}

/* ===== Reduced Motion (WCAG 2.3.3 AAA) ===== */

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

/* ===== High Contrast Mode ===== */

@media (forced-colors: active) {
  .nav-item.active {
    border: 2px solid Highlight;
  }
  .case-badge-icon {
    forced-color-adjust: none;
  }
}