/* ==========================================================================
   GET ENGINEERING SEAT — Foundation Reusable Components (v1.0)
   Authoritative Reference: docs/05-FRONTEND.md & docs/02-ui-ux-branding.md
   ========================================================================== */

/* ==========================================================================
   1. Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-none);
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  transition: background-color var(--transition-fast),
              border-color var(--transition-fast),
              color var(--transition-fast),
              box-shadow var(--transition-fast),
              transform var(--transition-fast);
  text-decoration: none !important;
  user-select: none;
  white-space: nowrap;
}

.btn:active:not(:disabled) {
  transform: translateY(1px);
}

/* Button Variants */
.btn-primary,
a.btn-primary,
button.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-on-primary, #ffffff) !important;
}
.btn-primary:hover:not(:disabled),
a.btn-primary:hover:not(:disabled),
button.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-dark);
  color: var(--color-on-primary, #ffffff) !important;
}

.btn-secondary,
a.btn-secondary,
button.btn-secondary {
  background-color: var(--color-secondary);
  color: var(--color-on-secondary, #ffffff) !important;
}
.btn-secondary:hover:not(:disabled),
a.btn-secondary:hover:not(:disabled),
button.btn-secondary:hover:not(:disabled) {
  background-color: var(--color-secondary-dark);
  color: var(--color-on-secondary, #ffffff) !important;
}

.btn-secondary span,
a.btn-secondary span,
button.btn-secondary span {
  color: var(--color-on-secondary, #ffffff) !important;
}

.btn-outline,
a.btn-outline,
button.btn-outline {
  background-color: transparent;
  border-color: var(--color-border-hover);
  color: var(--color-text);
}
.btn-outline:hover:not(:disabled),
a.btn-outline:hover:not(:disabled),
button.btn-outline:hover:not(:disabled) {
  border-color: var(--color-secondary);
  color: var(--color-secondary);
  background-color: var(--color-surface-hover);
}

[data-theme="dark"] .btn-outline,
[data-theme="dark"] a.btn-outline,
[data-theme="dark"] button.btn-outline {
  border-color: #475569;
  color: var(--color-text);
}
[data-theme="dark"] .btn-outline:hover:not(:disabled),
[data-theme="dark"] a.btn-outline:hover:not(:disabled),
[data-theme="dark"] button.btn-outline:hover:not(:disabled) {
  border-color: var(--color-teal-bright, #2dd4bf);
  color: var(--color-teal-bright, #2dd4bf);
  background-color: rgba(45, 212, 191, 0.1);
}

.btn-text,
a.btn-text,
button.btn-text {
  background-color: transparent;
  border-color: transparent;
  color: var(--color-text-secondary);
  padding-left: var(--spacing-2);
  padding-right: var(--spacing-2);
}
.btn-text:hover:not(:disabled),
a.btn-text:hover:not(:disabled),
button.btn-text:hover:not(:disabled) {
  color: var(--color-secondary);
  background-color: var(--color-surface-hover);
}

[data-theme="dark"] .btn-text,
[data-theme="dark"] a.btn-text,
[data-theme="dark"] button.btn-text {
  color: var(--color-teal-bright, #2dd4bf);
}
[data-theme="dark"] .btn-text:hover:not(:disabled),
[data-theme="dark"] a.btn-text:hover:not(:disabled),
[data-theme="dark"] button.btn-text:hover:not(:disabled) {
  color: var(--color-secondary-light, #5eead4);
  background-color: rgba(45, 212, 191, 0.08);
}

/* Button Sizes */
.btn-sm {
  font-size: var(--font-size-xs);
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-sm);
}

.btn-lg {
  font-size: var(--font-size-base);
  padding: 0.875rem 1.75rem;
  border-radius: var(--radius-lg);
}

/* Disabled & Loading */
.btn:disabled,
.btn[disabled],
.btn.disabled {
  opacity: 0.55;
  cursor: not-allowed !important;
  pointer-events: none;
  box-shadow: none !important;
}

.btn-loading {
  position: relative;
  color: transparent !important;
  pointer-events: none;
}

.btn-loading::after {
  content: '';
  position: absolute;
  width: 1rem;
  height: 1rem;
  top: calc(50% - 0.5rem);
  left: calc(50% - 0.5rem);
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

/* ==========================================================================
   2. Badges
   ========================================================================== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-none);
  padding: 0.25rem 0.625rem;
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.badge-default,
.badge-neutral {
  background-color: var(--color-surface-hover);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
}

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

.badge-warning {
  background-color: var(--color-warning-bg);
  color: var(--color-warning-text);
  border: 1px solid rgba(217, 119, 6, 0.2);
}

.badge-danger {
  background-color: var(--color-danger-bg);
  color: var(--color-danger-text);
  border: 1px solid rgba(234, 88, 12, 0.2);
}

.badge-info {
  background-color: var(--color-info-bg);
  color: var(--color-info-text);
  border: 1px solid rgba(37, 99, 235, 0.2);
}

/* ==========================================================================
   3. Cards
   ========================================================================== */
.card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-6);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base),
              transform var(--transition-base),
              border-color var(--transition-base);
}

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

.card-interactive {
  cursor: pointer;
}

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

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-4);
  padding-bottom: var(--spacing-4);
  border-bottom: 1px solid var(--color-border);
}

.card-body {
  flex: 1 1 auto;
}

.card-footer {
  margin-top: var(--spacing-4);
  padding-top: var(--spacing-4);
  border-top: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ==========================================================================
   4. Form Controls
   ========================================================================== */
.form-group {
  margin-bottom: var(--spacing-4);
}

.form-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  margin-bottom: var(--spacing-1);
}

.form-label-required::after {
  content: ' *';
  color: var(--color-error);
}

.form-control {
  display: block;
  width: 100%;
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 0.625rem 0.875rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control::placeholder {
  color: var(--color-placeholder);
}

.form-control:focus {
  outline: none;
  border-color: var(--color-secondary);
  box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}

[data-theme="dark"] .form-control:focus {
  border-color: var(--color-teal-bright, #2dd4bf);
  box-shadow: 0 0 0 3px rgba(45, 212, 191, 0.25);
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%2364748b' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  background-size: 1.25em 1.25em;
  padding-right: 2.5rem;
}

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

/* Checkbox & Radio */
.form-check {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  cursor: pointer;
  user-select: none;
  font-size: var(--font-size-sm);
}

.form-check input[type="checkbox"],
.form-check input[type="radio"] {
  width: 1.125rem;
  height: 1.125rem;
  accent-color: var(--color-secondary);
  cursor: pointer;
}

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

/* Validation Feedback */
.form-control.is-invalid {
  border-color: var(--color-error);
}

.form-control.is-invalid:focus {
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.15);
}

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

.form-feedback-error {
  display: block;
  font-size: var(--font-size-xs);
  color: var(--color-error);
  margin-top: 4px;
}

/* ==========================================================================
   5. Feedback & States
   ========================================================================== */
/* Alerts */
.alert {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-3);
  padding: var(--spacing-4);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-4);
  font-size: var(--font-size-sm);
}

.alert-success {
  background-color: var(--color-success-bg);
  color: var(--color-success-text);
  border-left: 4px solid var(--color-success);
}

.alert-warning {
  background-color: var(--color-warning-bg);
  color: var(--color-warning-text);
  border-left: 4px solid var(--color-warning);
}

.alert-danger,
.alert-error {
  background-color: var(--color-error-bg);
  color: var(--color-error-text);
  border-left: 4px solid var(--color-error);
}

.alert-info {
  background-color: var(--color-info-bg);
  color: var(--color-info-text);
  border-left: 4px solid var(--color-info);
}

/* Toasts */
.toast-container {
  position: fixed;
  bottom: var(--spacing-6);
  right: var(--spacing-6);
  z-index: var(--z-toast, 600);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  min-width: 280px;
  max-width: 420px;
  padding: var(--spacing-4);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-elevated);
  font-size: var(--font-size-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-3);
  animation: toast-slide-in var(--transition-base);
}

@keyframes toast-slide-in {
  from {
    transform: translateY(100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* Spinners */
.spinner {
  width: 1.5rem;
  height: 1.5rem;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-secondary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  display: inline-block;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Skeleton Loaders */
.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-surface-hover) 25%,
    var(--color-border) 37%,
    var(--color-surface-hover) 63%
  );
  background-size: 400% 100%;
  border-radius: var(--radius-sm);
  animation: skeleton-shimmer 1.4s ease infinite;
}

@keyframes skeleton-shimmer {
  0%   { background-position: 100% 50%; }
  100% { background-position: 0 50%; }
}

/* Empty & Error State Containers */
.empty-state,
.error-state {
  text-align: center;
  padding: var(--spacing-12) var(--spacing-4);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.empty-state-icon,
.error-state-icon {
  width: 3.5rem;
  height: 3.5rem;
  border-radius: 50%;
  background-color: var(--color-surface-hover);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-4);
  color: var(--color-text-muted);
}

.error-state-icon {
  background-color: var(--color-error-bg);
  color: var(--color-error);
}

.empty-state-title,
.error-state-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-2);
}

.empty-state-desc,
.error-state-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  max-width: 420px;
  margin-bottom: var(--spacing-6);
}

/* ==========================================================================
   6. Modal
   ========================================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal-backdrop, 500);
  background-color: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-4);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
}

.modal-backdrop.is-open {
  opacity: 1;
  visibility: visible;
}

.modal-dialog {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-elevated);
  width: 100%;
  max-width: 540px;
  max-height: 90vh;
  overflow-y: auto;
  transform: scale(0.95);
  transition: transform var(--transition-base);
}

.modal-backdrop.is-open .modal-dialog {
  transform: scale(1);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-4) var(--spacing-6);
  border-bottom: 1px solid var(--color-border);
}

.modal-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: 0;
}

.modal-close {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-1);
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.modal-body {
  padding: var(--spacing-6);
}

.modal-footer {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--spacing-3);
  padding: var(--spacing-4) var(--spacing-6);
  border-top: 1px solid var(--color-border);
}

/* --- Global Search Modal & Components --- */
.modal-dialog-search {
  max-width: 640px;
  width: 92%;
  max-height: 85vh;
  margin: var(--spacing-8) auto;
  display: flex;
  flex-direction: column;
}

.search-kbd-shortcut {
  font-size: 10px;
  font-family: monospace;
  background: var(--color-surface-raised, rgba(0, 0, 0, 0.05));
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 1px 5px;
  color: var(--color-text-muted);
  margin-left: var(--spacing-1);
}

.search-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  margin-bottom: var(--spacing-2);
}

.search-input-icon {
  position: absolute;
  left: var(--spacing-3);
  font-size: 18px;
  color: var(--color-text-muted);
  pointer-events: none;
}

.search-modal-input {
  padding-left: 42px !important;
  padding-right: 38px !important;
  height: 46px;
  font-size: var(--font-size-base) !important;
  width: 100%;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  color: var(--color-text);
}

.search-clear-btn {
  position: absolute;
  right: var(--spacing-3);
  background: none;
  border: none;
  font-size: 20px;
  color: var(--color-text-muted);
  cursor: pointer;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: var(--radius-full);
}

.search-clear-btn:hover {
  color: var(--color-text);
  background-color: var(--color-surface-hover);
}

.search-status-message {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  padding: var(--spacing-1) 0;
  min-height: 24px;
}

.search-results-container {
  overflow-y: auto;
  max-height: calc(85vh - 180px);
  margin-top: var(--spacing-2);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-3);
}

.search-category-group {
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-3);
}

.search-category-group:first-child {
  border-top: none;
  padding-top: 0;
}

.search-category-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: var(--font-weight-bold);
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-2);
}

.search-items-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.search-item-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-2) var(--spacing-3);
  border-radius: var(--radius-md);
  text-decoration: none !important;
  color: var(--color-text);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.search-item-link:hover,
.search-item-link:focus-visible {
  background-color: var(--color-surface-hover);
  color: var(--color-secondary);
}

.search-item-main {
  display: flex;
  flex-direction: column;
  gap: 2px;
  overflow: hidden;
}

.search-item-title {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.search-item-subtitle {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.search-empty-state {
  text-align: center;
  padding: var(--spacing-6) var(--spacing-4);
  color: var(--color-text-muted);
}

.search-empty-title {
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-base);
  margin-bottom: var(--spacing-1);
  color: var(--color-text);
}

.search-empty-hint {
  font-size: var(--font-size-xs);
  margin-bottom: 0;
}

/* --- Breadcrumb Navigation Component --- */
.breadcrumb-bar {
  background-color: var(--color-surface-raised, #f8fafc);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-2) 0;
  font-size: var(--font-size-xs);
}

[data-theme="dark"] .breadcrumb-bar {
  background-color: var(--color-surface);
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-2);
  list-style: none;
  margin: 0;
  padding: 0;
}

.breadcrumb-item {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-2);
  color: var(--color-text-muted);
}

.breadcrumb-item + .breadcrumb-item::before {
  content: '/';
  color: var(--color-text-muted);
  font-size: 10px;
}

.breadcrumb-link {
  color: var(--color-text-secondary);
  text-decoration: none !important;
  transition: color var(--transition-fast);
}

.breadcrumb-link:hover {
  color: var(--color-secondary);
  text-decoration: underline !important;
}

.breadcrumb-current {
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
}

/* --- Public Shell Header & Layout --- */
.public-page-header {
  padding: var(--spacing-8) 0 var(--spacing-6);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.public-header-badge {
  margin-bottom: var(--spacing-2);
}

.public-page-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--spacing-2);
  letter-spacing: -0.02em;
}

.public-page-description {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  max-width: 800px;
  margin-bottom: 0;
  line-height: var(--line-height-relaxed);
}

.public-page-body {
  padding: var(--spacing-8) 0;
}

.public-shell-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-6);
  box-shadow: var(--shadow-sm);
}

.public-shell-status {
  display: flex;
  gap: var(--spacing-4);
  align-items: flex-start;
  padding: var(--spacing-4);
  background-color: var(--color-surface-raised);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--color-secondary);
  margin-bottom: var(--spacing-6);
}

.public-shell-status .status-icon {
  font-size: 28px;
  line-height: 1;
  color: var(--color-secondary);
}

.public-shell-status .status-heading {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-1);
}

.public-shell-status .status-message {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: 0;
}

.public-shell-status .status-meta {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: var(--spacing-2);
  margin-bottom: 0;
}

.directory-links-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-4);
}

.directory-links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-4);
}

.directory-quick-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
  padding: var(--spacing-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none !important;
  color: var(--color-text);
  background-color: var(--color-surface);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
}

.directory-quick-link:hover,
.directory-quick-link:focus-visible {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-secondary);
}

.quick-link-icon {
  font-size: 24px;
  line-height: 1;
}

.quick-link-body {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.quick-link-title {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
}

.quick-link-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

/* --- 404 Not Found Card --- */
.not-found-wrapper {
  padding: var(--spacing-12) 0;
}

.not-found-card {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-8);
  box-shadow: var(--shadow-sm);
}

.not-found-badge {
  margin-bottom: var(--spacing-4);
}

.not-found-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-3);
}

.not-found-message {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-2);
}

.not-found-hint {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-6);
}

.not-found-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--spacing-3);
}