/* ============================================
   AI 튜터 맑은샘 - Settings Area Styles
   Flat Modern Theme (Bootstrap 5)
   ============================================ */

:root {
  /* Flat Modern Palette (Settings) */
  --flat-bg: #f5f7fa;
  --flat-card: #ffffff;
  --flat-border: #e8ecf1;
  --flat-text: #2d3748;
  --flat-text-muted: #718096;
  --flat-primary: #5a67d8;
  --flat-primary-hover: #4c51bf;
}

/* ============================================
   Custom Breakpoint - xxxl (1600px)
   ============================================ */

@media (min-width: 1600px) {
  .col-xxxl-6 {
    flex: 0 0 auto;
    width: 50%;
  }
}

/* ============================================
   Header Card - Hero Style
   ============================================ */

.header-card {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  border-radius: 16px;
  padding: 24px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  box-shadow: 0 10px 40px rgba(102, 126, 234, 0.3);
}

.header-icon {
  width: 56px;
  height: 56px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  color: white;
  backdrop-filter: blur(10px);
}

.header-content {
  flex: 1;
  min-width: 150px;
}

.header-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: white;
  margin: 0 0 4px 0;
  letter-spacing: -0.5px;
}

.header-subtitle {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.8);
  margin: 0;
}

.header-actions {
  display: flex;
  gap: 8px;
}

.btn-header-primary {
  background: white;
  color: #667eea;
  border: none;
  border-radius: 10px;
  padding: 10px 20px;
  font-weight: 600;
  font-size: 0.875rem;
  transition: all 0.2s ease;
}

.btn-header-primary:hover {
  background: rgba(255, 255, 255, 0.9);
  color: #5a67d8;
  transform: translateY(-1px);
}

.btn-header-secondary {
  background: rgba(255, 255, 255, 0.15);
  color: white;
  border: none;
  border-radius: 10px;
  padding: 10px 14px;
  transition: all 0.2s ease;
}

.btn-header-secondary:hover {
  background: rgba(255, 255, 255, 0.25);
  color: white;
}

/* ============================================
   Settings Area - Flat Modern Style
   ============================================ */

/* Flat Buttons */
.btn-primary {
  background-color: var(--flat-primary) !important;
  border: none !important;
  border-radius: 6px !important;
  font-weight: 500 !important;
  transition: background-color 0.2s ease !important;
}

.btn-primary:hover {
  background-color: var(--flat-primary-hover) !important;
}

.btn-outline-secondary {
  color: var(--flat-text-muted) !important;
  border: 1px solid var(--flat-border) !important;
  background: transparent !important;
  border-radius: 6px !important;
}

.btn-outline-secondary:hover {
  background-color: var(--flat-bg) !important;
  color: var(--flat-text) !important;
  border-color: var(--flat-border) !important;
}

/* Settings Cards */
.card {
  border: none !important;
  border-radius: 14px !important;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06) !important;
  background: var(--flat-card) !important;
  transition: box-shadow 0.2s ease;
}

.card:hover {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08) !important;
}

.card-header {
  background-color: transparent !important;
  border-bottom: 1px solid var(--flat-border) !important;
  padding: 18px 20px !important;
}

.card-body {
  padding: 20px !important;
}

.card-title {
  color: var(--flat-text) !important;
  font-weight: 600 !important;
  font-size: 1rem !important;
}

.card-title i {
  opacity: 0.7;
}

/* Flat Text Colors */
.text-primary {
  color: var(--flat-primary) !important;
}

h1, h5.card-title {
  color: var(--flat-text);
}

.text-muted {
  color: var(--flat-text-muted) !important;
}

/* Settings Labels */
.form-label {
  font-size: 0.875rem;
  color: var(--flat-text);
  margin-bottom: 8px;
}

.form-text {
  font-size: 0.75rem;
  color: var(--flat-text-muted);
  margin-top: 6px;
}

/* Flat Badges */
.badge.bg-primary {
  background-color: var(--flat-primary) !important;
  font-weight: 500 !important;
  font-size: 0.75rem !important;
  padding: 5px 10px !important;
  border-radius: 6px !important;
}

.badge.bg-secondary {
  background-color: #e2e8f0 !important;
  color: var(--flat-text) !important;
  font-weight: 500 !important;
  font-size: 0.75rem !important;
  padding: 5px 10px !important;
  border-radius: 6px !important;
}

/* Flat Form Controls */
.form-control,
.form-select {
  border: 1px solid var(--flat-border) !important;
  border-radius: 6px !important;
  transition: border-color 0.2s ease !important;
}

.form-control:focus,
.form-select:focus {
  border-color: var(--flat-primary) !important;
  box-shadow: none !important;
}

/* Modern Range Slider */
.form-range {
  height: 6px;
  background: #e2e8f0;
  border-radius: 3px;
}

.form-range::-webkit-slider-thumb {
  width: 18px;
  height: 18px;
  background: var(--flat-primary);
  border: 3px solid white;
  box-shadow: 0 2px 6px rgba(90, 103, 216, 0.3);
  border-radius: 50%;
  cursor: pointer;
  transition: transform 0.15s ease;
}

.form-range::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

.form-range::-moz-range-thumb {
  width: 18px;
  height: 18px;
  background: var(--flat-primary);
  border: 3px solid white;
  box-shadow: 0 2px 6px rgba(90, 103, 216, 0.3);
  border-radius: 50%;
  cursor: pointer;
}

.form-range:focus::-webkit-slider-thumb {
  box-shadow: 0 0 0 4px rgba(90, 103, 216, 0.2);
}

/* ============================================
   Learning Materials - Content Type Tabs
   ============================================ */

.content-type-tabs {
  display: flex;
  gap: 8px;
  background: var(--flat-bg);
  padding: 6px;
  border-radius: 10px;
}

.content-type-tab {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 10px 8px;
  border: none;
  background: transparent;
  color: var(--flat-text-muted);
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.content-type-tab i {
  font-size: 1.1rem;
}

.content-type-tab:hover {
  color: var(--flat-primary);
  background: rgba(90, 103, 216, 0.05);
}

.content-type-tab.active {
  background: white;
  color: var(--flat-primary);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

/* Content Forms */
.content-form {
  display: none;
}

.content-form.active {
  display: block;
}

/* Selected File Display */
.selected-file {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  background: #e8f4fd;
  border-radius: 8px;
  margin-bottom: 12px;
  color: var(--flat-text);
  font-size: 0.875rem;
}

.selected-file i {
  color: var(--flat-primary);
  font-size: 1.1rem;
}

.selected-file span {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn-clear-file {
  width: 20px;
  height: 20px;
  border: none;
  background: transparent;
  color: var(--flat-text-muted);
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  transition: all 0.15s ease;
}

.btn-clear-file:hover {
  background: rgba(0, 0, 0, 0.1);
  color: var(--flat-text);
}

/* ============================================
   Document Upload Area
   ============================================ */

.upload-area {
  border: 2px dashed var(--flat-border);
  border-radius: 12px;
  padding: 24px 16px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
  background: var(--flat-bg);
  margin-bottom: 16px;
}

.upload-area:hover {
  border-color: var(--flat-primary);
  background: rgba(90, 103, 216, 0.04);
}

.upload-area.dragover {
  border-color: var(--flat-primary);
  background: rgba(90, 103, 216, 0.08);
  transform: scale(1.01);
}

.upload-area__icon {
  font-size: 32px;
  color: var(--flat-primary);
  margin-bottom: 8px;
  opacity: 0.8;
}

.upload-area__text {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.upload-area__title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--flat-text);
}

.upload-area__subtitle {
  font-size: 0.75rem;
  color: var(--flat-text-muted);
}

/* Upload Progress */
.upload-progress {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 16px;
  background: var(--flat-bg);
  border-radius: 8px;
  margin-bottom: 16px;
}

.upload-progress__spinner {
  width: 20px;
  height: 20px;
  border: 2px solid var(--flat-border);
  border-top-color: var(--flat-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.upload-progress__text {
  font-size: 0.875rem;
  color: var(--flat-text);
}

/* Document List */
.document-list {
  max-height: 200px;
  overflow-y: auto;
}

.document-list__empty {
  text-align: center;
  color: var(--flat-text-muted);
  font-size: 0.875rem;
  padding: 16px 0;
  margin: 0;
}

.document-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  background: var(--flat-bg);
  border-radius: 8px;
  margin-bottom: 8px;
  transition: background 0.15s ease;
}

.document-item:last-child {
  margin-bottom: 0;
}

.document-item:hover {
  background: #edf2f7;
}

.document-item__icon {
  width: 36px;
  height: 36px;
  background: white;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  color: var(--flat-primary);
  flex-shrink: 0;
  margin-right: 10px;
}

.document-item__info {
  flex: 1;
  min-width: 0;
}

.document-item__title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--flat-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.document-item__meta {
  font-size: 0.75rem;
  color: var(--flat-text-muted);
  margin-top: 2px;
}

.document-item__delete {
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--flat-text-muted);
  font-size: 18px;
  cursor: pointer;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
  flex-shrink: 0;
  margin-left: 8px;
}

.document-item__delete:hover {
  background: #fee2e2;
  color: #dc2626;
}

/* Document List Scrollbar */
.document-list::-webkit-scrollbar {
  width: 4px;
}

.document-list::-webkit-scrollbar-track {
  background: transparent;
}

.document-list::-webkit-scrollbar-thumb {
  background: var(--flat-border);
  border-radius: 2px;
}

/* ============================================
   Chat Sessions List
   ============================================ */

.session-list {
  max-height: calc(100vh - 200px);
  overflow-y: auto;
  padding: 12px;
}

.session-list__empty {
  text-align: center;
  color: var(--flat-text-muted);
  font-size: 0.875rem;
  padding: 40px 16px;
  margin: 0;
}

.session-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px;
  background: var(--flat-bg);
  border-radius: 10px;
  margin-bottom: 10px;
  cursor: pointer;
  transition: all 0.2s ease;
  border: 2px solid transparent;
}

.session-item:last-child {
  margin-bottom: 0;
}

.session-item:hover {
  background: #edf2f7;
}

.session-item.active {
  background: rgba(90, 103, 216, 0.08);
  border-color: var(--flat-primary);
}

.session-item__icon {
  width: 40px;
  height: 40px;
  background: white;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  color: var(--flat-primary);
  flex-shrink: 0;
}

.session-item.active .session-item__icon {
  background: var(--flat-primary);
  color: white;
}

.session-item__content {
  flex: 1;
  min-width: 0;
}

.session-item__title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--flat-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 4px;
}

.session-item__preview {
  font-size: 0.75rem;
  color: var(--flat-text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 4px;
}

.session-item__meta {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.7rem;
  color: var(--flat-text-muted);
}

.session-item__meta i {
  font-size: 0.65rem;
}

.session-item__actions {
  display: flex;
  flex-direction: column;
  gap: 4px;
  opacity: 0;
  transition: opacity 0.2s ease;
}

.session-item:hover .session-item__actions {
  opacity: 1;
}

.session-item__btn {
  width: 26px;
  height: 26px;
  border: none;
  background: transparent;
  color: var(--flat-text-muted);
  font-size: 14px;
  cursor: pointer;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}

.session-item__btn:hover {
  background: rgba(0, 0, 0, 0.08);
  color: var(--flat-text);
}

.session-item__btn--delete:hover {
  background: #fee2e2;
  color: #dc2626;
}

/* Session List Scrollbar */
.session-list::-webkit-scrollbar {
  width: 4px;
}

.session-list::-webkit-scrollbar-track {
  background: transparent;
}

.session-list::-webkit-scrollbar-thumb {
  background: var(--flat-border);
  border-radius: 2px;
}

.session-list::-webkit-scrollbar-thumb:hover {
  background: var(--flat-primary);
}

/* ============================================
   Utilities
   ============================================ */

[hidden] {
  display: none !important;
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 575.98px) {
  .header-card {
    padding: 20px;
  }

  .header-title {
    font-size: 1.25rem;
  }

  .header-actions {
    width: 100%;
    justify-content: flex-start;
  }

  .btn-header-primary {
    flex: 1;
  }
}