*,
:after,
:before {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
[role="button"],
a,
button,
input,
label,
select {
  touch-action: manipulation;
}
body,
html {
  background: var(--color-primary-bg);
  font-family:
    DM Sans,
    system-ui,
    sans-serif;
  color: var(--color-text);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeSpeed;
}
#root,
body,
html {
  height: 100%;
}
#app-shell {
  display: flex;
  flex-direction: column;
  height: 100vh;
  width: 100vw;
  contain: strict;
}
#tab-strip {
  display: flex;
  align-items: flex-end;
  background: var(--color-secondary-bg);
  padding: 9px 9px 0;
  gap: 2px;
  border-bottom: 1px solid var(--border-subtle);
  min-height: 48px;
  flex-shrink: 0;
  overflow-x: auto;
  overflow-y: visible;
  overscroll-behavior-x: contain;
  scrollbar-width: none;
  position: relative;
  z-index: 110;
  contain: layout style;
}
#tab-strip::-webkit-scrollbar {
  display: none;
}
#tab-container {
  display: flex;
  gap: 2px;
  align-items: flex-end;
  min-width: 0;
}
.tab-item {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 0 10px;
  height: 37px;
  min-width: 140px;
  max-width: 220px;
  border-radius: 8px 8px 0 0;
  background: var(--color-surface);
  border: 1px solid transparent;
  border-bottom: none;
  cursor: pointer;
  font-size: 12px;
  font-weight: 500;
  color: var(--color-text-muted);
  flex-shrink: 0;
  position: relative;
  user-select: none;
  transition:
    background-color 0.15s,
    color 0.15s;
  contain: layout style paint;
}
.tab-item.active {
  background: var(--color-primary-bg);
  border-color: var(--border-subtle);
  color: var(--color-text);
  z-index: 2;
}
.tab-item.active:after {
  content: "";
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-primary-bg);
}
.tab-item:hover:not(.active) {
  background: var(--color-surface-hover);
  color: var(--color-text-dim);
}
.tab-favicon {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  flex-shrink: 0;
  background: var(--color-surface);
  object-fit: contain;
}
.tab-label {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 12px;
}
.tab-close {
  width: 18px;
  height: 18px;
  border-radius: 4px;
  border: none;
  background: 0 0;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  transition:
    background-color 0.15s,
    color 0.15s;
  flex-shrink: 0;
  opacity: 0;
}
.tab-item.active .tab-close,
.tab-item:hover .tab-close {
  opacity: 1;
}
.tab-close:hover {
  background: #ff4d4d33;
  color: #ff4b4b;
}
#new-tab-btn {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  background: 0 0;
  border: 1px solid transparent;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-bottom: 4px;
  transition:
    background-color 0.15s,
    color 0.15s,
    border-color 0.15s;
}
#new-tab-btn:hover {
  background: var(--color-surface-hover);
  border-color: var(--border-default);
  color: var(--color-text);
}
#omnibar {
  gap: 5px;
  padding: 8px 12px;
  background: var(--color-primary-bg);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 109;
  contain: layout style;
}
#omnibar,
.omni-btn {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}
.omni-btn {
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: 0 0;
  border: none;
  color: var(--color-text-dim);
  cursor: pointer;
  transition:
    background-color 0.15s,
    color 0.15s,
    transform 0.1s;
}
.omni-btn:hover {
  background: var(--color-surface-hover);
  color: var(--color-text);
}
.omni-btn:active {
  transform: scale(0.91);
}
.omni-btn svg {
  width: 17px;
  height: 17px;
  stroke-width: 2.2;
  pointer-events: none;
}
#omnibar-actions {
  display: flex;
  align-items: center;
  gap: 1px;
  flex-shrink: 0;
}
#address-bar-wrap {
  flex: 1;
  position: relative;
  display: flex;
  align-items: center;
}
#course-search-input {
  width: 100%;
  height: 36px;
  padding: 0 42px 0 14px;
  background: var(--color-surface);
  border: 1px solid var(--border-default);
  border-radius: 20px;
  color: var(--color-text);
  font-family:
    DM Mono,
    monospace;
  font-size: 12px;
  letter-spacing: 0.01em;
  outline: 0;
  transition:
    background-color 0.18s,
    border-color 0.18s,
    box-shadow 0.18s;
}
#course-search-input::placeholder {
  color: var(--color-text-muted);
  font-family:
    DM Sans,
    sans-serif;
  font-size: 12.5px;
}
#course-search-input:hover {
  background: var(--color-surface-hover);
  border-color: var(--border-strong);
}
#course-search-input:focus {
  background: var(--color-surface-hover);
  border-color: var(--color-accent-main);
  box-shadow: 0 0 0 3px var(--color-surface-hover);
}
#bookmark-star-btn {
  position: absolute;
  right: 10px;
  background: 0 0;
  border: none;
  cursor: pointer;
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  padding: 4px;
  transition:
    color 0.15s,
    transform 0.15s,
    background-color 0.15s;
  z-index: 2;
  border-radius: 5px;
}
#bookmark-star-btn:hover {
  color: var(--color-text);
  transform: scale(1.1);
  background: var(--color-surface-hover);
}
#bookmark-star-btn.bookmarked {
  color: #f5c518;
}
#bookmark-star-btn.bookmarked svg {
  fill: #f5c518;
}
#bookmark-star-btn svg {
  width: 16px;
  height: 16px;
  stroke-width: 2;
}
#suggestions-dropdown {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  background: var(--color-secondary-bg);
  border: 1px solid var(--border-default);
  border-radius: 12px;
  overflow: hidden;
  z-index: 500;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.6);
  display: none;
}
#suggestions-dropdown.visible {
  display: block;
}
.suggestion-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  cursor: pointer;
  font-size: 13px;
  color: var(--color-text-dim);
  transition: background-color 0.12s;
  border-bottom: 1px solid var(--border-subtle);
  contain: layout style paint;
  content-visibility: auto;
}
.suggestion-item:last-child {
  border-bottom: none;
}
.suggestion-item.active,
.suggestion-item:hover {
  background: var(--color-surface-hover);
  color: var(--color-text);
}
.suggestion-item svg {
  flex-shrink: 0;
  opacity: 0.4;
  width: 14px;
  height: 14px;
}
.suggestion-text {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.suggestion-fill {
  font-size: 11px;
  color: var(--color-text-muted);
  opacity: 0.5;
  flex-shrink: 0;
  padding-left: 6px;
}
#content-area {
  flex: 1;
  position: relative;
  overflow: hidden;
  background: var(--color-primary-bg);
  contain: strict;
}
#educational-background-canvas {
  width: 100%;
  height: 100%;
  z-index: 1;
}
#content-viewer,
#educational-background-canvas {
  position: absolute;
  inset: 0;
  pointer-events: none;
  contain: strict;
}
#content-viewer {
  z-index: 6;
  background: 0 0;
}
#content-viewer.active {
  background: var(--color-primary-bg);
  pointer-events: auto;
}
iframe {
  border: none;
  width: 100%;
  height: 100%;
  display: block;
  background-color: transparent !important;
  color-scheme: light;
  contain: strict;
  transform: translateZ(0);
  will-change: contents;
}
#education-home {
  position: absolute;
  inset: 0;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 40px 200px;
  width: 100%;
  contain: layout style;
}
.logo-text {
  font-family:
    DM Sans,
    sans-serif;
  font-weight: 700;
  font-size: 72px;
  letter-spacing: -4px;
  background: linear-gradient(
    160deg,
    var(--color-text-muted) 0,
    var(--color-text) 40%,
    var(--color-text-muted) 100%
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 30px;
  line-height: 1;
  user-select: none;
}
.home-search-wrap {
  width: 100%;
  max-width: 600px;
  margin: 0 auto 40px;
  padding: 0 20px;
}
.shortcuts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(80px, 80px));
  justify-content: center;
  gap: 16px;
  width: 100%;
  max-width: 600px;
  contain: layout style;
}
#main-search-bar {
  width: 100%;
  padding: 16px 20px;
  font-size: 16px;
  border-radius: 8px;
  background: var(--color-surface);
  border: 1px solid var(--border-default);
  color: var(--color-text);
  font-family:
    DM Sans,
    sans-serif;
  outline: 0;
  transition:
    border-color 0.2s,
    background-color 0.2s,
    box-shadow 0.2s;
}
#main-search-bar::placeholder {
  color: var(--color-text-muted);
}
#main-search-bar:focus,
#main-search-bar:hover {
  background: var(--color-surface-hover);
}
#main-search-bar:focus {
  border-color: var(--color-accent-main);
  box-shadow: 0 0 0 3px var(--color-surface-hover);
}
.shortcut-tile {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1/1;
  background: 0 0;
  border: none;
  border-radius: var(--radius-md);
  color: var(--color-text);
  cursor: pointer;
  transition:
    transform 0.2s,
    background-color 0.2s;
  padding: 8px;
  contain: layout style paint;
  content-visibility: auto;
}
.shortcut-tile:hover {
  transform: scale(1.05);
  background: var(--color-surface-hover);
}
.shortcut-tile:hover .delete-shortcut,
.shortcut-tile:hover .edit-shortcut {
  opacity: 1;
}
.shortcut-tile img {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  margin-bottom: 8px;
  pointer-events: none;
}
.shortcut-tile span {
  font-size: 11px;
  font-weight: 500;
  opacity: 0.7;
  text-align: center;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.delete-shortcut {
  position: absolute;
  top: 4px;
  right: 4px;
  width: 20px;
  height: 20px;
  background: #ff4d4df2;
  border: none;
  border-radius: 50%;
  color: #fff;
  font-size: 13px;
  cursor: pointer;
  opacity: 0;
  transition:
    opacity 0.2s,
    transform 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
}
.delete-shortcut:hover {
  background: #ff4d4d;
  transform: scale(1.15);
}
.edit-shortcut {
  position: absolute;
  top: 4px;
  left: 4px;
  width: 20px;
  height: 20px;
  border: none;
  border-radius: 50%;
  color: #fff;
  cursor: pointer;
  opacity: 0;
  transition:
    opacity 0.2s,
    transform 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  padding: 0;
  background: var(--color-surface-hover);
}
.edit-shortcut:hover {
  transform: scale(1.15);
}
.edit-shortcut svg {
  width: 11px;
  height: 11px;
  stroke-width: 2.5;
  pointer-events: none;
}
#resource-loading-overlay {
  position: absolute;
  inset: 0;
  background-color: var(--color-primary-bg);
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  z-index: 10;
  gap: 16px;
  transition: opacity 0.2s ease;
  contain: layout style paint;
  will-change: opacity;
}
#resource-loading-overlay.visible {
  display: flex;
}
.loader-spinner {
  width: 48px;
  height: 48px;
  border: 3px solid var(--border-subtle);
  border-top-color: var(--color-accent-main);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  will-change: transform;
}
#resource-loading-message {
  color: var(--color-text-dim);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.3px;
}
@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(1turn);
  }
}
.modal {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--color-secondary-bg);
  padding: 24px;
  border-radius: var(--radius-lg);
  z-index: 300;
  border: 1px solid var(--border-default);
  width: 360px;
  box-shadow: 0 32px 64px rgba(0, 0, 0, 0.75);
  max-height: 80vh;
  overflow-y: auto;
  overscroll-behavior: contain;
  contain: layout style;
  will-change: transform;
}
.hidden {
  display: none !important;
}
.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
}
.clear-all-btn,
.modal-header h2 {
  font-size: 11px;
  text-transform: uppercase;
}
.modal-header h2 {
  margin: 0;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--color-text-muted);
}
.clear-all-btn {
  background: 0 0;
  border: none;
  color: #ff4b4b;
  font-weight: 600;
  cursor: pointer;
  letter-spacing: 1px;
}
.clear-all-btn:hover {
  opacity: 0.7;
}
.list-container {
  max-height: 380px;
  overflow-y: auto;
  overscroll-behavior: contain;
  display: flex;
  flex-direction: column;
  gap: 6px;
  contain: layout style;
}
.list-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 11px 14px;
  background: var(--color-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition:
    background-color 0.2s,
    border-color 0.2s;
  cursor: pointer;
  contain: layout style paint;
  content-visibility: auto;
}
.list-item:hover {
  background: var(--color-surface-hover);
  border-color: var(--border-default);
}
.setting-row {
  flex-direction: column;
  align-items: flex-start;
  gap: 5px;
  cursor: default;
}
.setting-label {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-text-muted);
}
.setting-control {
  width: 100%;
  background: 0 0;
  border: none;
  color: var(--color-text);
  font-size: 14px;
  font-weight: 500;
  outline: 0;
  padding: 3px 0;
  cursor: pointer;
  appearance: none;
}
.setting-control option {
  background: var(--color-secondary-bg);
  color: var(--color-text);
}
.modal-close-btn {
  width: 100%;
  margin-top: 18px;
  padding: 13px;
  background: var(--color-text);
  color: var(--color-primary-bg);
  border: none;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 13px;
  cursor: pointer;
  transition: opacity 0.2s;
}
.modal-close-btn:hover {
  opacity: 0.88;
}
.secondary-btn {
  width: 100%;
  margin-top: 7px;
  padding: 10px;
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s;
}
.secondary-btn:hover {
  background: var(--color-surface-hover);
}
.add-new-tab-btn {
  width: 100%;
  padding: 13px;
  background: var(--color-surface);
  border: 1px solid var(--color-accent-main);
  border-radius: var(--radius-md);
  color: var(--color-accent-main);
  font-weight: 600;
  font-size: 13px;
  cursor: pointer;
  transition: background-color 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 10px;
}
.add-new-tab-btn:hover {
  background: var(--color-surface-hover);
}
.tab-modal-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px;
  background: var(--color-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition:
    background-color 0.2s,
    border-color 0.2s;
  cursor: pointer;
  gap: 12px;
  contain: layout style paint;
  content-visibility: auto;
}
.tab-modal-item:hover {
  background: var(--color-surface-hover);
  border-color: var(--border-default);
}
.tab-modal-item.active {
  background: var(--color-surface-hover);
  border-color: var(--color-accent-main);
}
.tab-modal-favicon {
  width: 18px;
  height: 18px;
  border-radius: 4px;
  flex-shrink: 0;
  background: var(--color-surface);
}
.tab-info {
  display: flex;
  align-items: center;
  gap: 10px;
}
.tab-info,
.tab-text {
  flex: 1;
  overflow: hidden;
}
.tab-modal-title,
.tab-modal-url {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.tab-modal-title {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 3px;
}
.tab-modal-url {
  font-size: 11px;
  color: var(--color-text-muted);
}
.tab-close-btn {
  width: 26px;
  height: 26px;
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  border: 1px solid var(--border-default);
  color: var(--color-text);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition:
    background-color 0.2s,
    border-color 0.2s,
    color 0.2s;
  flex-shrink: 0;
  font-size: 17px;
  opacity: 0.6;
}
.tab-close-btn:hover {
  background: #ff4b4b2e;
  border-color: #ff4b4b;
  color: #ff4b4b;
  opacity: 1;
}
.history-item-content {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1;
  overflow: hidden;
}
.history-favicon {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  flex-shrink: 0;
}
.history-text {
  flex: 1;
  overflow: hidden;
}
.history-url {
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.history-time {
  font-size: 10px;
  color: var(--color-text-muted);
  margin-top: 2px;
}
.history-delete-btn {
  width: 22px;
  height: 22px;
  border-radius: 5px;
  background: var(--color-surface);
  border: 1px solid var(--border-default);
  color: var(--color-text);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition:
    background-color 0.2s,
    border-color 0.2s,
    color 0.2s;
  flex-shrink: 0;
  font-size: 15px;
  opacity: 0.55;
}
.history-delete-btn:hover {
  background: #ff4b4b2e;
  border-color: #ff4b4b;
  color: #ff4b4b;
  opacity: 1;
}
.form-group {
  margin-bottom: 14px;
}
.form-group label {
  display: block;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--color-text-muted);
  margin-bottom: 7px;
}
.form-group input {
  width: 100%;
  padding: 9px 13px;
  background: var(--color-surface);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  font-size: 14px;
  outline: 0;
  transition:
    background-color 0.2s,
    border-color 0.2s;
}
.form-group input:focus {
  background: var(--color-surface-hover);
  border-color: var(--border-strong);
}
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: 0 0;
}
::-webkit-scrollbar-thumb {
  background: var(--border-subtle);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--border-default);
}
* {
  scrollbar-width: thin;
  scrollbar-color: var(--border-subtle) transparent;
}
@media (prefers-reduced-motion: reduce) {
  *,
  :after,
  :before {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .loader-spinner {
    animation: none;
    border-top-color: var(--color-accent-main);
  }
}