:root {
  --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --corner-radius: 2px;
  --search-width: 470px;
  --search-height: 40px;
  --search-submit-width: 50px;
  --primary-color: #2d2d2d;
  --secondary-color: #888;
  --border-color: #d0d0d0;
  --light-color: #f6f6f6;
  --mid-color: #dfdfdf;
  --dark-color: #4c4c4c;
  --white-color: #fff;
  --danger-color: #de8971;
  --success-color: #96bb7c;
  --highlight-color: var(--dark-color);
  --base-background: #ededed;
  --main-background: var(--white-color);
  --block-background: var(--light-color);
  --input-background: var(--white-color);
  --focus-background: var(--light-color);
  --search-background: var(--light-color);
  --setting-background: #eaeaea;
  --panel-background: var(--main-background);
}

[data-color-mode="dark"]:root {
  --primary-color: #ddd;
  --secondary-color: #aaa;
  --border-color: var(--mid-color);
  --light-color: #4a4a4a;
  --mid-color: #2c2c2c;
  --dark-color: #ababab;
  --danger-color: #3f0713;
  --success-color: #1e5128;
  --highlight-color: var(--light-color);
  --base-background: #161616;
  --main-background: #222;
  --block-background: #1c1c1c;
  --input-background: #3c3c3c;
  --focus-background: #1c1c1c;
  --search-background: #282828;
  --setting-background: #282828;
}

*,:after,:before { box-sizing: border-box; }
blockquote,body,dd,dl,figure,h1,h2,h3,h4,p { margin: 0; }
ol,ul { padding: 0; margin: 0; list-style: none; }
html { -webkit-text-size-adjust: 100%; -webkit-font-smoothing: antialiased; -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
button,input,select,textarea { padding: 0; border: 0; margin: 0; font: inherit; appearance: none; }
:focus { outline: none; }
::placeholder { color: var(--secondary-color); }

body {
  max-width: 1440px;
  padding: 24px 80px;
  margin: 0 auto;
  font-family: var(--font-base);
  font-size: 16px;
  line-height: 1.25;
  background: var(--base-background);
  transition: background .2s ease-out;
  color: var(--primary-color);
}

/* Header */
.header {
  display: flex;
  height: 64px;
  padding: 0 40px;
  margin-bottom: 24px;
  line-height: 1;
  color: var(--dark-color);
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
}

.logo {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: .5px;
  transition: color .1s ease;
  cursor: pointer;
}

.logo:hover { color: var(--primary-color); }

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

.header-btn {
  padding: 8px;
  margin-right: -8px;
  font-size: 20px;
  color: var(--dark-color);
  cursor: pointer;
  background: none;
  border: none;
  transition: color .1s ease;
}

.header-btn:hover { color: var(--primary-color); }

.header-btn.active { color: var(--primary-color); }

/* Footer */
.footer {
  padding: 0 40px;
  margin-top: 24px;
  font-size: 14px;
  color: var(--secondary-color);
  border-top: 1px solid var(--border-color);
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px 0;
}

.footer-links { display: flex; align-items: center; }
.footer-link {
  margin: 0 12px;
  transition: color .1s ease;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
}
.footer-link:hover { color: var(--primary-color); }

.footer-copyright {
  margin-top: 8px;
  font-size: 12px;
  opacity: .5;
}

/* Search */
.search-section {
  padding: 0 0 32px;
}

.search-wrapper {
  position: relative;
  max-width: var(--search-width);
  margin: 0 auto;
}

.search-box {
  display: flex;
  height: var(--search-height);
  border-radius: var(--corner-radius);
  background: var(--search-background);
}

.engine-switch {
  display: flex;
  height: 100%;
  padding: 0 10px;
  color: var(--dark-color);
  opacity: .64;
  align-items: center;
  cursor: pointer;
  transition: opacity .1s ease;
  border: none;
  background: none;
}

.engine-switch:hover { opacity: .88; }

.engine-icon { width: 28px; height: 28px; }
.engine-key { margin-left: 6px; font-size: 10px; }

.search-input {
  width: 100%;
  margin-left: 4px;
  line-height: 1.5;
  color: var(--primary-color);
  background: none;
  flex: 1;
  border: none;
  font-size: 16px;
}

.autocomplete-btn {
  display: flex;
  padding: 0 10px;
  margin-right: 8px;
  color: var(--secondary-color);
  font-size: 16px;
  cursor: pointer;
  align-items: center;
  opacity: .8;
  transition: color .1s ease;
  background: none;
  border: none;
}

.autocomplete-btn:hover { color: var(--primary-color); }

.search-submit {
  width: var(--search-submit-width);
  border-radius: 0 var(--corner-radius) var(--corner-radius) 0;
  color: var(--dark-color);
  font-size: 18px;
  cursor: pointer;
  background: transparent;
  transition: color .1s ease, background .1s ease-in-out;
  border: none;
}

.search-submit:hover,
.search-submit:focus { color: var(--white-color); background: var(--highlight-color); }

/* Autocomplete Dropdown */
.autocomplete-dropdown {
  position: absolute;
  z-index: 100;
  width: calc(100% - var(--search-submit-width));
  border: 1px solid var(--border-color);
  margin-top: -1px;
  border-radius: 0 0 var(--corner-radius) var(--corner-radius);
  color: var(--primary-color);
  background: var(--panel-background);
  max-height: 290px;
  overflow-y: auto;
  display: none;
}

.autocomplete-dropdown.show { display: block; }

.autocomplete-item {
  padding: 8px 20px;
  cursor: pointer;
  font-size: 15px;
}

.autocomplete-item:hover { background: var(--focus-background); }

/* Engine Dropdown */
.engine-dropdown {
  position: absolute;
  z-index: 100;
  min-width: 190px;
  border: 1px solid var(--border-color);
  margin-top: -1px;
  border-radius: 0 0 var(--corner-radius) var(--corner-radius);
  color: var(--primary-color);
  background: var(--panel-background);
  max-height: 290px;
  overflow-y: auto;
  display: none;
  letter-spacing: .02em;
}

.engine-dropdown.show { display: block; }

.engine-dropdown-header {
  display: flex;
  justify-content: space-around;
  font-size: 10px;
  font-weight: 500;
  line-height: 18px;
  color: var(--secondary-color);
  text-align: center;
  letter-spacing: .05em;
  background: var(--block-background);
  padding: 6px 0;
}

.engine-item {
  display: flex;
  align-items: center;
  padding: 8px 12px;
  cursor: pointer;
}

.engine-item:hover { background: var(--focus-background); }

.engine-item-icon {
  width: 20px;
  height: 20px;
  margin-right: 8px;
  opacity: .64;
}

.engine-item-name { max-width: 120px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.engine-item-key { max-width: 80px; margin-left: 16px; color: var(--secondary-color); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* Navigation */
.nav-section {
  background: var(--block-background);
  border-radius: var(--corner-radius);
}

.nav-wrapper {
  position: relative;
  max-width: 1130px;
  padding: 0 40px;
  margin: 0 auto;
  overflow: hidden;
}

.nav-tabs-container {
  position: relative;
  padding: 20px 0;
  font-size: 0;
  text-align: center;
  white-space: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}

.nav-tabs-container::-webkit-scrollbar { display: none; }

.nav-tabs {
  display: inline-flex;
  gap: 0;
}

.nav-tab {
  display: inline-block;
  height: 42px;
  padding: 10px 20px;
  border-bottom: 2px solid transparent;
  margin-right: 20px;
  overflow: hidden;
  color: var(--secondary-color);
  font-size: 16px;
  white-space: nowrap;
  cursor: pointer;
  transition: color .1s ease, border-color .1s ease;
}

.nav-tab:last-child { margin-right: 0; }
.nav-tab.active,
.nav-tab:hover { color: var(--primary-color); border-bottom-color: var(--secondary-color); }

/* Navigation Content */
.nav-content { padding-bottom: 32px; }

.nav-group {
  position: relative;
  display: flex;
  margin-bottom: 16px;
}

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

.group-name-col {
  position: relative;
  display: flex;
  max-width: 10%;
  overflow: hidden;
  color: var(--secondary-color);
  align-items: center;
  flex: 0 0 10%;
}

.group-name {
  white-space: nowrap;
  font-size: 14px;
}

.group-links-col {
  display: flex;
  max-width: 90%;
  overflow: hidden;
  flex: 0 0 90%;
  flex-wrap: wrap;
}

.link-item {
  max-width: 16.666667%;
  flex: 0 0 16.666667%;
  text-align: left;
}

.link-inner {
  position: relative;
  display: inline-flex;
  max-width: 100%;
  padding: 8px;
  border-radius: var(--corner-radius);
  overflow: hidden;
  transition: background .1s ease-out;
  align-items: center;
}

.link-inner:hover { background: var(--mid-color); }

.link-icon {
  width: 20px;
  height: 20px;
  margin-right: 8px;
  flex-shrink: 0;
}

.link-icon.fade { opacity: .8; filter: grayscale(50%); }
.link-icon.gray { filter: grayscale(100%); }

.link-name {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-size: 14px;
}

/* Edit Mode */
.edit-mode .nav-section { position: relative; }

.btn {
  padding: 6px 16px;
  border-radius: var(--corner-radius);
  font-size: 14px;
  cursor: pointer;
  border: 1px solid var(--border-color);
  background: var(--main-background);
  color: var(--primary-color);
  transition: background .1s ease;
}

.btn:hover { background: var(--light-color); }
.btn-primary { background: var(--primary-color); color: var(--white-color); border-color: var(--primary-color); }
.btn-primary:hover { opacity: .85; }
.btn-danger { color: var(--danger-color); border-color: var(--danger-color); }
.btn-danger:hover { background: var(--danger-color); color: var(--white-color); }

/* Editable items in edit mode */
.link-delete { display: none; }
.edit-mode .link-inner:hover { background: transparent; }
.edit-mode .nav-tab { cursor: grab; position: relative; }
.edit-mode .nav-tab:active { cursor: grabbing; }

.edit-mode .tab-delete,
.edit-mode .tab-add-btn {
  display: inline-block;
}

.tab-delete {
  display: none;
  margin-left: 8px;
  font-size: 12px;
  color: var(--danger-color);
  cursor: pointer;
  opacity: .6;
}

.tab-delete:hover { opacity: 1; }

.tab-add-btn {
  display: none;
  margin-left: 8px;
  font-size: 14px;
  color: var(--secondary-color);
  cursor: pointer;
}

.tab-add-btn:hover { color: var(--primary-color); }

.edit-mode .link-item { position: relative; }
.edit-mode .link-inner { cursor: pointer; }

.edit-mode .group-name-col { cursor: pointer; }

.edit-mode .link-delete,
.edit-mode .group-delete {
  display: none;
  position: absolute;
  top: 2px;
  right: 4px;
  font-size: 12px;
  color: var(--danger-color);
  cursor: pointer;
  z-index: 5;
  opacity: .6;
}

.edit-mode .link-delete:hover,
.edit-mode .group-delete:hover { opacity: 1; }
.edit-mode .link-inner:hover .link-delete { display: block; }

.link-add,
.group-add,
.group-add-btn {
  display: none;
  cursor: pointer;
  color: var(--secondary-color);
  font-size: 14px;
  padding: 8px;
}

.link-add:hover,
.group-add:hover,
.group-add-btn:hover { color: var(--primary-color); }

.edit-mode .link-add,
.edit-mode .group-add,
.edit-mode .group-add-btn { display: inline-flex; }

/* Edit Panel (popup) */
.edit-panel-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 200;
  background: rgba(0,0,0,.3);
}

.edit-panel-overlay.show { display: block; }

.edit-panel {
  position: fixed;
  z-index: 210;
  background: var(--main-background);
  border: 1px solid var(--border-color);
  border-radius: var(--corner-radius);
  padding: 16px;
  box-shadow: 0 4px 16px rgba(0,0,0,.18);
  min-width: 280px;
  max-width: 360px;
}

.edit-panel h3 {
  font-size: 16px;
  margin-bottom: 16px;
  color: var(--primary-color);
}

.edit-field {
  margin-bottom: 12px;
}

.edit-field label {
  display: block;
  font-size: 13px;
  color: var(--secondary-color);
  margin-bottom: 4px;
}

.edit-field input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border-color);
  border-radius: var(--corner-radius);
  font-size: 14px;
  color: var(--primary-color);
  background: var(--input-background);
}

.edit-field input:focus { border-color: var(--secondary-color); }
.edit-field input.invalid { border-color: var(--danger-color); }

.edit-panel-buttons {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}

/* Drag and Drop */
.dragging { opacity: .5; }
.drag-over { border-top: 2px solid var(--primary-color); }

/* Settings Page */
.setting-page {
  max-width: 700px;
  margin: 0 auto;
  padding: 20px;
}

.setting-page h1 {
  font-size: 22px;
  margin-bottom: 20px;
  color: var(--primary-color);
}

.setting-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px 20px;
}

.setting-group {
  margin-bottom: 0;
}

.setting-group label {
  display: block;
  font-size: 12px;
  color: var(--secondary-color);
  margin-bottom: 4px;
}

.setting-group select {
  width: 100%;
  padding: 6px 8px;
  border: 1px solid var(--border-color);
  border-radius: var(--corner-radius);
  font-size: 13px;
  color: var(--primary-color);
  background: var(--input-background);
}

.sync-section {
  margin-top: 20px;
  padding: 16px;
  background: var(--block-background);
  border-radius: var(--corner-radius);
}

.sync-section h2 {
  font-size: 15px;
  margin-bottom: 10px;
  color: var(--primary-color);
}

.sync-input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border-color);
  border-radius: var(--corner-radius);
  font-size: 13px;
  margin-bottom: 8px;
  color: var(--primary-color);
  background: var(--input-background);
}

.sync-buttons {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.sync-alert {
  margin-top: 8px;
  padding: 6px 10px;
  border-radius: var(--corner-radius);
  font-size: 12px;
}

.sync-alert.error { background: var(--danger-color); color: var(--white-color); }
.sync-alert.success { background: var(--success-color); color: var(--white-color); }

.setting-actions {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}

@media screen and (max-width: 600px) {
  .setting-grid { grid-template-columns: 1fr; }
}

/* About Page */
.about-page {
  max-width: 600px;
  margin: 0 auto;
  padding: 20px;
  color: var(--primary-color);
  line-height: 1.8;
}

.about-page h1 { font-size: 24px; margin-bottom: 16px; }
.about-page h2 { font-size: 18px; margin: 24px 0 12px; }
.about-page p { margin-bottom: 12px; }
.about-page a { color: var(--primary-color); text-decoration: underline; }
.about-page a:hover { opacity: .7; }

/* Responsive */
@media screen and (max-width: 1200px) {
  body { padding: 40px; }
}

@media screen and (max-width: 834px) {
  body { padding: 20px; }
  .header { height: 56px; padding: 0 24px; }
  .footer { padding: 0 24px; }
  .nav-wrapper { max-width: 100%; padding: 0 32px; }
  .nav-tab { height: 38px; padding: 8px 10px; margin-right: 10px; }
  .link-item { padding: 4px; }
  .link-icon { margin-right: 4px; }
}

@media screen and (max-width: 600px) {
  body { padding: 0; }
  .header { height: 48px; padding: 0 16px; }
  .logo { font-size: 28px; }
  .header-btn { font-size: 16px; }
  .footer { padding: 0 16px; }
  .search-section { padding: 8px 0 48px; }
  .search-wrapper { max-width: 100%; margin: 0 20px; }
  .search-box { height: 40px; }
  .engine-icon { width: 22px; height: 22px; }
  .engine-key { margin-left: 4px; font-size: 8px; }
  .search-submit { width: 48px; font-size: 16px; }
  .nav-wrapper { padding: 0 20px; }
  .nav-tabs-container { padding: 16px 0; margin: 0 -20px; }
  .nav-tab { height: 28px; padding: 4px 5px; margin-right: 16px; font-size: 15px; }
  .nav-content { padding-bottom: 28px; }
  .nav-group { margin-bottom: 14px; }
  .group-name-col { max-width: 15%; flex: 0 0 15%; }
  .group-links-col { max-width: 85%; flex: 0 0 85%; }
  .link-item { max-width: 33.333%; flex: 0 0 33.333%; }
  .link-icon { width: 18px; height: 18px; }
}