/* ============================================================================
   QueryLab Modern Design System
   Color Palette: Navy, Cyan, Purple | Clean, Professional, Modern
   ============================================================================ */

:root {
  /* ===== COLORS ===== */
  --primary-dark: #0f172a;      /* Deep navy */
  --primary: #1e293b;            /* Navy */
  --primary-light: #334155;      /* Light navy */
  --accent: #00d9ff;             /* Vibrant cyan */
  --accent-dark: #0099cc;        /* Dark cyan */
  --secondary: #7c3aed;          /* Electric purple */
  --secondary-light: #a78bfa;    /* Light purple */
  
  --success: #10b981;            /* Green */
  --warning: #f59e0b;            /* Amber */
  --error: #ef4444;              /* Red */
  --info: #3b82f6;               /* Blue */
  
  --neutral-50: #f9fafb;
  --neutral-100: #f3f4f6;
  --neutral-200: #e5e7eb;
  --neutral-300: #d1d5db;
  --neutral-400: #9ca3af;
  --neutral-500: #6b7280;
  --neutral-600: #4b5563;
  --neutral-700: #374151;
  --neutral-800: #1f2937;
  --neutral-900: #111827;
  
  /* ===== SEMANTIC ===== */
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --bg-tertiary: #f3f4f6;
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-tertiary: #9ca3af;
  --border: #e5e7eb;
  
  /* ===== DIFFICULTY COLORS ===== */
  --easy: #10b981;
  --easy-bg: rgba(16, 185, 129, 0.1);
  --medium: #f59e0b;
  --medium-bg: rgba(245, 158, 11, 0.1);
  --hard: #ef4444;
  --hard-bg: rgba(239, 68, 68, 0.1);
  
  /* ===== SPACING ===== */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 12px;
  --spacing-lg: 16px;
  --spacing-xl: 24px;
  --spacing-2xl: 32px;
  --spacing-3xl: 48px;
  
  /* ===== TYPOGRAPHY ===== */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, "Helvetica Neue", sans-serif;
  --font-mono: "SF Mono", "Monaco", "Inconsolata", "Fira Code", monospace;
  
  /* ===== SHADOWS ===== */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* ===== TRANSITIONS ===== */
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: all 0.15s ease-out;
}

[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-tertiary: #94a3b8;
  --border: #334155;
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
}

/* ============================================================================
   GLOBAL STYLES
   ============================================================================ */

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  width: 100%;
  height: 100%;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.6;
  transition: background-color var(--transition-fast);
}

/* ============================================================================
   TYPOGRAPHY
   ============================================================================ */

h1 { font-size: 2.5rem; font-weight: 700; line-height: 1.2; letter-spacing: -0.5px; }
h2 { font-size: 1.875rem; font-weight: 700; line-height: 1.2; margin-top: var(--spacing-2xl); margin-bottom: var(--spacing-lg); }
h3 { font-size: 1.25rem; font-weight: 600; line-height: 1.3; }
h4 { font-size: 1.125rem; font-weight: 600; }
h5 { font-size: 1rem; font-weight: 600; }
h6 { font-size: 0.875rem; font-weight: 600; }

p { margin-bottom: var(--spacing-lg); }
a { color: var(--accent); text-decoration: none; transition: var(--transition-fast); }
a:hover { color: var(--accent-dark); }

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-tertiary);
  padding: 2px 6px;
  border-radius: 4px;
}

pre {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: var(--spacing-lg);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

pre code {
  background: none;
  padding: 0;
}

kbd {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

/* ============================================================================
   HEADER
   ============================================================================ */

.header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.95);
}

[data-theme="dark"] .header {
  background-color: rgba(15, 23, 42, 0.95);
}

.header-content {
  max-width: 1600px;
  margin: 0 auto;
  padding: var(--spacing-lg) var(--spacing-xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-xl);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  font-weight: 700;
  font-size: 1.5rem;
  cursor: pointer;
}

.logo-emoji {
  font-size: 1.75rem;
}

.logo-name em {
  font-style: normal;
  color: var(--accent);
}

.header-nav {
  display: flex;
  gap: var(--spacing-2xl);
  flex: 1;
  margin-left: var(--spacing-2xl);
}

.nav-link {
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition-fast);
}

.nav-link:hover {
  color: var(--accent);
}

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

/* ============================================================================
   BUTTONS
   ============================================================================ */

.btn {
  border: none;
  border-radius: 6px;
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  white-space: nowrap;
  user-select: none;
  font-family: var(--font-sans);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

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

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

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

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

.btn-accent {
  background: var(--accent);
  color: var(--primary-dark);
  font-weight: 700;
}

.btn-accent:hover:not(:disabled) {
  background: var(--accent-dark);
}

.btn-outline {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-primary);
}

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

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}

.btn-ghost:hover:not(:disabled) {
  color: var(--accent);
}

.btn-small { padding: var(--spacing-xs) var(--spacing-md); font-size: 0.8125rem; }
.btn-large { padding: var(--spacing-md) var(--spacing-2xl); font-size: 1rem; }
.btn-block { width: 100%; }

/* ============================================================================
   MODALS
   ============================================================================ */

.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 1;
  transition: opacity var(--transition-fast);
}

.modal.hidden {
  display: none;
  opacity: 0;
  pointer-events: none;
}

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

.modal-dialog {
  background: var(--bg-primary);
  border-radius: 12px;
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 420px;
  position: relative;
  z-index: 1;
  animation: slideUp 0.3s ease-out;
}

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

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

.modal-header h2 {
  margin: 0;
  font-size: 1.5rem;
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  transition: var(--transition-fast);
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-form {
  padding: var(--spacing-xl);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

/* ============================================================================
   FORMS
   ============================================================================ */

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

.form-group label {
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--text-primary);
}

input[type="text"],
input[type="email"],
input[type="password"],
select,
textarea {
  padding: var(--spacing-md) var(--spacing-lg);
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  transition: var(--transition-fast);
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
select:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--bg-tertiary);
}

.form-footer {
  text-align: center;
  font-size: 0.8125rem;
  color: var(--text-secondary);
  margin: 0;
}

.link-btn {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font-weight: 600;
  padding: 0;
}

.link-btn:hover {
  color: var(--accent-dark);
}

/* ============================================================================
   BADGES
   ============================================================================ */

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  white-space: nowrap;
}

.badge-easy {
  background: var(--easy-bg);
  color: var(--easy);
}

.badge-medium {
  background: var(--medium-bg);
  color: var(--medium);
}

.badge-hard {
  background: var(--hard-bg);
  color: var(--hard);
}

.badge-info {
  background: var(--bg-tertiary);
  color: var(--text-secondary);
}

.badge-success {
  background: rgba(16, 185, 129, 0.1);
  color: var(--success);
}

/* ============================================================================
   LAYOUT
   ============================================================================ */

.layout {
  display: flex;
  height: calc(100vh - 61px);
  gap: 0;
}

.sidebar {
  width: 320px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.main-content {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.panel {
  flex: 1;
  display: flex;
  flex-direction: column;
}

/* ============================================================================
   SIDEBAR
   ============================================================================ */

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

.sidebar-header h3 {
  margin: 0;
  font-size: 1rem;
}

.sidebar-search {
  padding: var(--spacing-lg);
}

.sidebar-search input {
  width: 100%;
}

.sidebar-filters {
  padding: 0 var(--spacing-lg) var(--spacing-lg);
  border-bottom: 1px solid var(--border);
}

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

.filter-group label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.filter-buttons {
  display: flex;
  gap: var(--spacing-xs);
}

.filter-btn {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: transparent;
  cursor: pointer;
  font-size: 0.75rem;
  font-weight: 600;
  transition: var(--transition-fast);
}

.filter-btn.active {
  background: var(--accent);
  color: var(--primary-dark);
  border-color: var(--accent);
}

.filter-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.filter-select {
  width: 100%;
}

.sidebar-actions {
  padding: 0 var(--spacing-lg) var(--spacing-lg);
  display: flex;
  gap: var(--spacing-sm);
  border-bottom: 1px solid var(--border);
}

.sidebar-actions .btn {
  flex: 1;
  font-size: 0.75rem;
}

.question-list {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-sm);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.question-item {
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition-fast);
  border-left: 3px solid transparent;
}

.question-item:hover {
  background: var(--bg-tertiary);
}

.question-item.active {
  background: var(--accent);
  color: var(--primary-dark);
  border-left-color: var(--primary-dark);
}

.question-item-title {
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 4px;
}

.question-item-meta {
  display: flex;
  gap: var(--spacing-sm);
  font-size: 0.75rem;
}

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

/* ============================================================================
   WELCOME PANEL
   ============================================================================ */

.welcome-panel {
  padding: var(--spacing-3xl);
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

.welcome-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.welcome-tagline {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin: var(--spacing-lg) 0 0 0;
}

.welcome-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-3xl);
}

.stat-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: var(--spacing-xl);
  text-align: center;
}

.stat-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: var(--spacing-sm);
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.welcome-content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-3xl);
}

.welcome-content section {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: var(--spacing-2xl);
}

.steps {
  list-style: none;
  counter-reset: step-counter;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.steps li {
  counter-increment: step-counter;
  display: flex;
  gap: var(--spacing-lg);
  align-items: flex-start;
}

.steps li::before {
  content: counter(step-counter);
  min-width: 32px;
  height: 32px;
  background: var(--accent);
  color: var(--primary-dark);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  flex-shrink: 0;
}

.path-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-xl);
}

.path-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: var(--spacing-xl);
  text-align: center;
  transition: var(--transition-fast);
}

.path-card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.path-number {
  width: 40px;
  height: 40px;
  background: var(--accent);
  color: var(--primary-dark);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  margin: 0 auto var(--spacing-md);
}

.path-card h3 {
  margin: 0 0 var(--spacing-sm);
}

.path-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin: 0;
}

.btn-large {
  margin-top: var(--spacing-2xl);
  width: 100%;
}

/* ============================================================================
   WORKSPACE PANEL
   ============================================================================ */

.workspace-panel {
  display: flex;
  flex-direction: column;
  height: 100%;
}

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

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.workspace-meta {
  display: flex;
  gap: var(--spacing-md);
}

.workspace-split {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 0;
  flex: 1;
  overflow: hidden;
}

.question-details {
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: var(--spacing-xl);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
}

.question-description {
  font-size: 0.95rem;
  line-height: 1.7;
}

.schema-box,
.hints-box,
.solution-box {
  border-top: 1px solid var(--border);
  padding-top: var(--spacing-lg);
}

.schema-box h3,
.hints-box h3,
.solution-box h3 {
  font-size: 1rem;
  margin-bottom: var(--spacing-md);
}

.editor-panel {
  display: flex;
  flex-direction: column;
  gap: 0;
}

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

.editor-header h3 {
  margin: 0;
  font-size: 1rem;
}

.editor-actions {
  display: flex;
  gap: var(--spacing-sm);
}

#sqlEditor {
  flex: 1;
  border: none;
  padding: var(--spacing-lg);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  resize: none;
}

.results-panel {
  border-top: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  min-height: 180px;
  max-height: 40%;
}

.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg) var(--spacing-xl);
  border-bottom: 1px solid var(--border);
  font-weight: 600;
}

.results-content {
  flex: 1;
  overflow: auto;
  padding: var(--spacing-lg);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
}

.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
}

.results-table th {
  background: var(--bg-tertiary);
  padding: var(--spacing-md);
  text-align: left;
  font-weight: 600;
  border-bottom: 1px solid var(--border);
}

.results-table td {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--border);
}

.workspace-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-lg) var(--spacing-xl);
  border-top: 1px solid var(--border);
  gap: var(--spacing-lg);
}

.workspace-progress {
  text-align: center;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

/* ============================================================================
   UTILITIES
   ============================================================================ */

.hidden {
  display: none !important;
}

.text-dim {
  color: var(--text-secondary);
}

.link {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.link:hover {
  color: var(--accent-dark);
  text-decoration: underline;
}

/* ============================================================================
   CODEMIRROR CUSTOMIZATION
   ============================================================================ */

.CodeMirror {
  height: 100% !important;
  background: var(--bg-primary) !important;
  color: var(--text-primary) !important;
  border: none !important;
}

.CodeMirror-gutters {
  background: var(--bg-secondary) !important;
  border-right: 1px solid var(--border) !important;
}

.CodeMirror-linenumber {
  color: var(--text-tertiary) !important;
}

.CodeMirror-cursor {
  border-left-color: var(--accent) !important;
}

/* ============================================================================
   RESPONSIVE
   ============================================================================ */

@media (max-width: 1024px) {
  .workspace-split {
    grid-template-columns: 1fr;
  }

  .question-details {
    border-right: none;
    border-bottom: 1px solid var(--border);
    max-height: 40%;
  }
}

@media (max-width: 768px) {
  .layout {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    max-height: 200px;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }

  .header-nav {
    display: none;
  }

  .welcome-panel {
    padding: var(--spacing-xl);
  }

  h1 {
    font-size: 1.875rem;
  }

  .welcome-stats {
    grid-template-columns: repeat(2, 1fr);
  }
}

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