/* KC7 Core Design System
 * Shared variables, utilities, and base components across all pages
 * Design direction: Precision & clarity with cool neutral foundation
 * Depth strategy: Borders-only with subtle surface color shifts
 */

/* ====================================
   CSS Custom Properties - Design Tokens
   ==================================== */
:root {
  /* Color System - Cool Neutral Foundation */
  --color-bg: #f8f9fa;
  --color-surface: #ffffff;
  --color-surface-raised: #fafbfc;
  --color-border: rgba(15, 23, 42, 0.08);
  --color-border-subtle: rgba(15, 23, 42, 0.05);

  /* Text Hierarchy */
  --color-text-primary: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #94a3b8;
  --color-text-faint: #cbd5e1;

  /* Accent Colors - Single blue for interactive elements */
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-accent-active: #1e40af; /* hover/pressed shade for SOLID accent buttons — accent-hover is for text/links and flips lighter in dark mode */
  --color-accent-light: #eff6ff;

  /* Semantic Colors - Meaningful only */
  --color-success: #16a34a;
  --color-success-hover: #15803d;
  --color-success-bg: #f0fdf4;
  --color-success-border: #bbf7d0;

  --color-warning: #f97316;
  --color-warning-hover: #ea580c;
  --color-warning-bg: #fff7ed;
  --color-warning-border: #fed7aa;

  --color-danger: #dc2626;
  --color-danger-bg: #fef2f2;
  --color-danger-border: #fecaca;

  /* Info pair for icon chips/badges. Named -text/-bg because --color-info
     is already claimed by core/custom.css (.text-info teal) with its own
     dark override. */
  --color-info-text: #3b82f6;
  --color-info-bg: #eff6ff;

  /* Row status tokens — question checklist coloring. Reference the semantic
     tokens above so they flip automatically under html[data-theme="dark"]. */
  --row-correct-border: var(--color-accent);
  --row-correct-bg: var(--color-accent-light);
  --row-incorrect-border: var(--color-warning);
  --row-incorrect-bg: var(--color-warning-bg);
  --row-muted-border: var(--color-text-faint);
  --row-muted-bg: var(--color-surface-raised);

  /* Competitive Rank Colors - Warm accents for achievements */
  --rank-gold: #d4af37;
  --rank-gold-subtle: rgba(212, 175, 55, 0.12);
  --rank-gold-text: #9d7e2a;

  --rank-silver: #94a3b8;
  --rank-silver-subtle: rgba(148, 163, 184, 0.12);

  --rank-bronze: #b8860b;
  --rank-bronze-subtle: rgba(184, 134, 11, 0.12);
  --rank-bronze-text: #8b6508;

  /* Depth - Subtle, borders-first */
  --shadow-subtle: 0 1px 3px rgba(15, 23, 42, 0.04);
  --shadow-focus: 0 0 0 3px rgba(37, 99, 235, 0.1);

  /* Spacing Scale - 4px Grid */
  --space-4: 4px;
  --space-8: 8px;
  --space-10: 10px;
  --space-12: 12px;
  --space-16: 16px;
  --space-20: 20px;
  --space-24: 24px;
  --space-32: 32px;

  /* Typography Scale */
  --font-size-xs: 11px;
  --font-size-sm: 12px;
  --font-size-base: 13px;
  --font-size-md: 14px;
  --font-size-lg: 16px;
  --font-size-xl: 18px;
  --font-size-2xl: 24px;
  --font-size-3xl: 28px;
  --font-size-4xl: 32px;

  /* Font Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-base: 6px;
  --radius-lg: 8px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-base: 150ms cubic-bezier(0.25, 1, 0.5, 1);
}

/* ====================================
   Base Typography
   ==================================== */
body {
  font-size: var(--font-size-md);
  color: var(--color-text-primary);
  line-height: 1.5;
}

/* Monospace for data */
.mono,
.tabular-nums {
  font-family: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', monospace;
  font-variant-numeric: tabular-nums;
}

/* ====================================
   Section Cards - Base pattern
   ==================================== */
.section-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-24);
  margin-bottom: var(--space-20);
}

.section-header {
  margin-bottom: var(--space-20);
  padding-bottom: var(--space-12);
  border-bottom: 1px solid var(--color-border-subtle);
}

.section-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  letter-spacing: -0.01em;
  color: var(--color-text-primary);
  margin: 0;
  display: flex;
  align-items: center;
  gap: var(--space-10);
}

.section-title i {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
}

.section-description {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  margin: var(--space-4) 0 0 0;
}

/* ====================================
   Stat Cards - Monospace numbers
   ==================================== */
.stat-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-20);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.stat-number {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-semibold);
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  line-height: 1;
  font-family: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', monospace;
  font-variant-numeric: tabular-nums;
}

.stat-label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
}

/* ====================================
   Buttons - Base patterns
   ==================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
  padding: var(--space-10) var(--space-16);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-base);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
  text-decoration: none;
}

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

.btn i {
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

/* Button variants */
.btn-primary {
  background: var(--color-accent);
  color: white;
  border-color: var(--color-accent);
}

.btn-primary:hover:not(:disabled) {
  background: var(--color-accent-active);
  border-color: var(--color-accent-active);
  color: white;
  text-decoration: none;
}

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

.btn-success:hover:not(:disabled) {
  background: #15803d;
  border-color: #15803d;
  color: white;
  text-decoration: none;
}

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

.btn-danger:hover:not(:disabled) {
  background: #b91c1c;
  border-color: #b91c1c;
  color: white;
  text-decoration: none;
}

/* OAuth branded buttons */
.btn-google {
  background: #ea4335;
  color: white;
  border-color: #ea4335;
}

.btn-google:hover:not(:disabled) {
  background: #d33426;
  border-color: #d33426;
  color: white;
  text-decoration: none;
}

.btn-microsoft {
  background: #00a4ef;
  color: white;
  border-color: #00a4ef;
}

.btn-microsoft:hover:not(:disabled) {
  background: #0090d1;
  border-color: #0090d1;
  color: white;
  text-decoration: none;
}

/* Button sizes */
.btn-block {
  width: 100%;
}

/* ====================================
   Form Elements - Base patterns
   ==================================== */
.form-group {
  margin-bottom: var(--space-16);
}

.form-group:last-child {
  margin-bottom: 0;
}

.form-label {
  display: block;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  margin-bottom: var(--space-8);
}

.form-input {
  width: 100%;
  padding: var(--space-10) var(--space-12);
  font-size: var(--font-size-md);
  color: var(--color-text-primary);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-base);
  transition: all var(--transition-base);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: var(--shadow-focus);
}

.form-input:disabled,
.form-input[readonly] {
  background: var(--color-bg);
  color: var(--color-text-muted);
  cursor: not-allowed;
}

.form-input::placeholder {
  color: var(--color-text-muted);
}

/* Input validation states */
.form-input.is-invalid {
  border-color: var(--color-danger);
}

.form-input.is-valid {
  border-color: var(--color-success);
}

.form-feedback {
  font-size: var(--font-size-sm);
  color: var(--color-danger);
  margin-top: var(--space-4);
  display: none;
}

.form-input.is-invalid ~ .form-feedback,
.is-invalid ~ .invalid-feedback {
  display: block;
}

.form-help {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-4);
}

/* Checkboxes */
.checkbox {
  display: flex;
  align-items: flex-start;
  gap: var(--space-10);
  margin-bottom: var(--space-12);
}

.checkbox-input {
  width: 18px;
  height: 18px;
  margin-top: 2px;
  cursor: pointer;
  accent-color: var(--color-accent);
  flex-shrink: 0;
}

.checkbox-label {
  flex: 1;
  font-size: var(--font-size-md);
  color: var(--color-text-primary);
  cursor: pointer;
  user-select: none;
}

.checkbox-label strong {
  font-weight: var(--font-weight-medium);
}

.checkbox-label small {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-4);
}

/* ====================================
   Info Boxes
   ==================================== */
.info-box {
  padding: var(--space-12) var(--space-16);
  border-radius: var(--radius-base);
  font-size: var(--font-size-base);
  margin-bottom: var(--space-16);
}

.info-box i {
  margin-right: var(--space-8);
}

.info-box-info {
  background: var(--color-accent-light);
  color: var(--color-text-secondary);
  border: 1px solid rgba(37, 99, 235, 0.15);
}

.info-box-info i {
  color: var(--color-accent);
}

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

.info-box-warning i {
  color: var(--color-warning);
}

.info-box-success {
  background: var(--color-success-bg);
  color: var(--color-text-secondary);
  border: 1px solid rgba(22, 163, 74, 0.2);
}

.info-box-success i {
  color: var(--color-success);
}

/* ====================================
   Notification Badge
   ==================================== */
.notification-badge {
  margin-left: auto;
  background: var(--color-danger);
  color: white;
  padding: 2px var(--space-8);
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  font-family: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', monospace;
  font-variant-numeric: tabular-nums;
}

/* ====================================
   Capability Grid - Reusable link grid
   ==================================== */
.capability-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-12);
}

.capability-link {
  display: flex;
  align-items: center;
  padding: var(--space-12) var(--space-16);
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-base);
  text-decoration: none;
  color: var(--color-text-secondary);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-base);
  position: relative;
}

.capability-link:hover {
  background: var(--color-accent-light);
  border-color: var(--color-accent);
  color: var(--color-accent);
  text-decoration: none;
}

.capability-link i {
  margin-right: var(--space-10);
  font-size: var(--font-size-lg);
  width: 20px;
  text-align: center;
  flex-shrink: 0;
}

/* ====================================
   Spacing Utilities - 4px Grid
   ==================================== */
.gap-4 { gap: var(--space-4); }
.gap-8 { gap: var(--space-8); }
.gap-12 { gap: var(--space-12); }
.gap-16 { gap: var(--space-16); }
.gap-20 { gap: var(--space-20); }
.gap-24 { gap: var(--space-24); }

.mb-4 { margin-bottom: var(--space-4); }
.mb-8 { margin-bottom: var(--space-8); }
.mb-12 { margin-bottom: var(--space-12); }
.mb-16 { margin-bottom: var(--space-16); }
.mb-20 { margin-bottom: var(--space-20); }
.mb-24 { margin-bottom: var(--space-24); }
.mb-32 { margin-bottom: var(--space-32); }

.mt-4 { margin-top: var(--space-4); }
.mt-8 { margin-top: var(--space-8); }
.mt-12 { margin-top: var(--space-12); }
.mt-16 { margin-top: var(--space-16); }
.mt-20 { margin-top: var(--space-20); }
.mt-24 { margin-top: var(--space-24); }
.mt-32 { margin-top: var(--space-32); }

/* ====================================
   Bootstrap Compatibility Classes
   ==================================== */
/* For backward compatibility with existing templates */
.invalid-feedback {
  font-size: var(--font-size-sm);
  color: var(--color-danger);
  margin-top: var(--space-4);
  display: none;
}

.is-invalid ~ .invalid-feedback {
  display: block;
}

/* ====================================
   Responsive Base Breakpoints
   ==================================== */
@media (max-width: 768px) {
  .capability-grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .stat-number {
    font-size: 28px;
  }

  .section-card {
    padding: var(--space-20) var(--space-16);
    margin-bottom: var(--space-16);
  }
}

@media (max-width: 480px) {
  :root {
    --font-size-3xl: 24px;
    --font-size-4xl: 28px;
  }
}