:root {
  color-scheme: light;
  --bg: #f4f7fb;
  --surface: #ffffff;
  --surface-soft: #f8faff;
  --ink: #172033;
  --muted: #6f7b91;
  --line: #e5eaf2;
  --primary: #5367dc;
  --primary-deep: #4255c5;
  --primary-soft: #eef0ff;
  --success: #16856b;
  --danger: #c64d5a;
  --shadow: 0 18px 50px rgba(35, 54, 92, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--bg);
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 80% -10%, rgba(133, 148, 255, 0.17), transparent 34rem),
    var(--bg);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

button,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}

button:focus-visible,
textarea:focus-visible,
.tool-nav-item:focus-visible,
.tool-search:focus-visible,
.tool-nav-category-summary:focus-visible,
.seo-tool-more summary:focus-visible {
  outline: 3px solid rgba(83, 103, 220, 0.25);
  outline-offset: 2px;
}

.page-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-header,
.main-layout,
.site-footer {
  width: min(1160px, calc(100% - 48px));
  margin: 0 auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 42px 0 34px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  color: #fff;
  background: linear-gradient(145deg, #7887ee, #4f61d2);
  border-radius: 14px;
  box-shadow: 0 10px 20px rgba(83, 103, 220, 0.25);
  font-size: 21px;
  font-weight: 700;
}

.eyebrow,
.section-label {
  margin: 0;
  color: var(--primary);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(22px, 3vw, 28px);
  letter-spacing: -0.04em;
}

.header-note {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.main-layout {
  display: grid;
  flex: 1;
  grid-template-columns: 246px minmax(0, 1fr);
  gap: 26px;
  padding-bottom: 46px;
}

.sidebar,
.tool-card {
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(229, 234, 242, 0.95);
  border-radius: 22px;
  box-shadow: var(--shadow);
}

.sidebar {
  align-self: start;
  padding: 20px 14px 14px;
}

.sidebar-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 0 10px 14px;
}

.tool-search-label {
  display: block;
  margin: 0 10px 7px;
  color: var(--muted);
  cursor: pointer;
  font-size: 11px;
  font-weight: 700;
  user-select: none;
  -webkit-user-select: none;
}

.tool-search-wrap {
  position: relative;
  margin: 0 4px;
}

.tool-search-icon {
  position: absolute;
  top: 50%;
  left: 11px;
  color: #9aa5b9;
  font-size: 19px;
  line-height: 1;
  pointer-events: none;
  transform: translateY(-54%);
}

.tool-search {
  width: 100%;
  min-height: 38px;
  padding: 0 11px 0 31px;
  color: var(--ink);
  background: #fbfcff;
  border: 1px solid var(--line);
  border-radius: 11px;
  cursor: text;
  font-size: 12px;
  user-select: text;
  -webkit-user-select: text;
}

.tool-search::placeholder {
  color: #a6afbf;
}

.tool-search-hint {
  margin: 8px 10px 15px;
  color: #9aa5b9;
  font-size: 11px;
  line-height: 1.5;
}

.tool-count {
  color: #a1aabc;
  font-size: 12px;
}

.tool-nav {
  display: grid;
  gap: 7px;
}

.tool-nav-section {
  display: grid;
  gap: 7px;
}

.tool-nav-section + .tool-nav-section {
  margin-top: 14px;
}

.tool-nav-section-title {
  margin: 0 10px 2px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.tool-nav-list {
  display: grid;
  gap: 5px;
}

.tool-nav-category-group {
  border-top: 1px solid #eef1f6;
}

.tool-nav-category-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
  font-size: 12px;
  font-weight: 700;
  user-select: none;
  -webkit-user-select: none;
}

.tool-nav-category-summary::-webkit-details-marker {
  display: none;
}

.tool-nav-category-summary::after {
  color: #9aa5b9;
  content: "+";
  font-size: 16px;
  font-weight: 400;
}

.tool-nav-category-group[open] .tool-nav-category-summary::after {
  content: "−";
}

.tool-nav-category-count {
  margin-left: auto;
  color: #a1aabc;
  font-size: 11px;
  font-weight: 500;
}

.tool-nav-category-group .tool-nav-list {
  padding: 0 0 5px;
}

.tool-nav-empty {
  margin: 0 10px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.6;
}

.tool-nav-item {
  display: flex;
  align-items: center;
  width: 100%;
  gap: 12px;
  padding: 11px 10px;
  color: var(--muted);
  text-align: left;
  text-decoration: none;
  background: transparent;
  border: 0;
  border-radius: 14px;
  cursor: pointer;
  transition: background 160ms ease, color 160ms ease, transform 160ms ease;
  user-select: none;
  -webkit-user-select: none;
}

.tool-nav-item:hover {
  color: var(--ink);
  background: var(--surface-soft);
  transform: translateX(2px);
}

.tool-nav-item.is-active {
  color: var(--primary-deep);
  background: var(--primary-soft);
}

.tool-icon {
  display: grid;
  width: 35px;
  height: 35px;
  flex: 0 0 35px;
  place-items: center;
  color: var(--primary-deep);
  background: #fff;
  border: 1px solid #e0e5ff;
  border-radius: 11px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 11px;
  font-weight: 800;
}

.tool-nav-copy {
  display: grid;
  gap: 2px;
}

.tool-nav-name {
  color: inherit;
  font-size: 14px;
}

.tool-nav-category {
  color: #a0a9ba;
  font-size: 11px;
}

.privacy-note {
  display: flex;
  gap: 9px;
  margin: 20px 4px 0;
  padding: 13px 10px;
  color: var(--muted);
  background: #fafbfe;
  border-radius: 13px;
}

.privacy-note p {
  margin: 0;
  font-size: 11px;
  line-height: 1.55;
}

.privacy-icon {
  color: var(--primary);
  font-size: 14px;
}

.workspace {
  min-width: 0;
  padding: 12px 0 0;
}

.workspace-intro {
  padding: 0 8px 20px;
}

.workspace-intro h2 {
  margin: 7px 0 7px;
  font-size: clamp(25px, 4vw, 34px);
  letter-spacing: -0.045em;
}

.workspace-intro p {
  max-width: 600px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.tool-card {
  padding: 20px;
}

.tool-toolbar,
.operation-group,
.utility-group {
  display: flex;
  align-items: center;
}

.tool-toolbar {
  justify-content: space-between;
  gap: 14px;
  padding-bottom: 18px;
}

.operation-group,
.utility-group {
  flex-wrap: wrap;
  gap: 8px;
}

.button {
  min-height: 38px;
  padding: 0 16px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 700;
  transition: background 160ms ease, border-color 160ms ease, color 160ms ease, transform 160ms ease;
}

.button:hover:not(:disabled) {
  transform: translateY(-1px);
}

.button-primary {
  color: #fff;
  background: var(--primary);
  box-shadow: 0 7px 14px rgba(83, 103, 220, 0.2);
}

.button-primary:hover:not(:disabled) {
  background: var(--primary-deep);
}

.button-secondary,
.button-ghost {
  color: var(--primary-deep);
  background: var(--primary-soft);
}

.button-secondary:hover:not(:disabled),
.button-ghost:hover:not(:disabled) {
  background: #e3e7ff;
}

.button-ghost {
  color: var(--muted);
  background: transparent;
  border-color: var(--line);
}

.button-ghost:hover:not(:disabled) {
  color: var(--ink);
  background: var(--surface-soft);
  border-color: #d4dbea;
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.editor-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.editor-grid-dual .editor-output-block {
  grid-column: 1 / -1;
}

.editor-block {
  min-width: 0;
}

.editor-label {
  display: block;
  margin: 0 0 8px;
  color: var(--ink);
  cursor: pointer;
  font-size: 13px;
  font-weight: 750;
  user-select: none;
  -webkit-user-select: none;
}

.editor-area {
  display: block;
  width: 100%;
  min-height: 340px;
  resize: vertical;
  padding: 15px;
  color: var(--ink);
  background: #fbfcff;
  border: 1px solid var(--line);
  border-radius: 14px;
  cursor: text;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.65;
  transition: border-color 160ms ease, box-shadow 160ms ease;
  user-select: text;
  -webkit-user-select: text;
}

.editor-area::placeholder {
  color: #adb7c9;
}

.editor-area:focus {
  border-color: #aab5ff;
  box-shadow: 0 0 0 4px rgba(83, 103, 220, 0.1);
  outline: 0;
}

.editor-output {
  color: #39486c;
  background: #f7f8ff;
}

.editor-meta {
  display: block;
  margin-top: 8px;
  color: #9aa5b9;
  font-size: 11px;
}

.rendered-preview {
  min-height: 160px;
  margin-top: 14px;
  padding: 20px;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  line-height: 1.7;
}

.rendered-preview h1,
.rendered-preview h2,
.rendered-preview h3 {
  margin: 0 0 12px;
  color: var(--primary-deep);
  line-height: 1.35;
}

.rendered-preview p,
.rendered-preview ul,
.rendered-preview ol,
.rendered-preview blockquote,
.rendered-preview pre {
  margin: 0 0 12px;
}

.rendered-preview blockquote {
  padding-left: 14px;
  color: var(--muted);
  border-left: 3px solid #c9d0ff;
}

.rendered-preview code {
  padding: 2px 5px;
  color: #7a3c61;
  background: #f7eef5;
  border-radius: 5px;
}

.rendered-preview pre {
  overflow-x: auto;
  padding: 12px;
  color: #edf1ff;
  background: #202943;
  border-radius: 10px;
}

.rendered-preview pre code {
  padding: 0;
  color: inherit;
  background: transparent;
}

.rendered-preview a {
  color: var(--primary-deep);
}

.result-image-preview {
  display: block;
  width: min(100%, 320px);
  max-height: 320px;
  margin: 16px auto 0;
  object-fit: contain;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.file-input {
  display: block;
  width: 100%;
  padding: 13px;
  color: var(--muted);
  background: #fbfcff;
  border: 1px dashed #cbd3e3;
  border-radius: 14px;
  font-size: 13px;
}

.file-list {
  display: grid;
  gap: 8px;
  margin-top: 10px;
}

.file-list-empty {
  margin: 0;
  padding: 10px 12px;
  color: #9aa5b9;
  background: #fbfcff;
  border: 1px solid var(--line);
  border-radius: 10px;
  font-size: 12px;
}

.file-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 10px 11px;
  background: #fbfcff;
  border: 1px solid var(--line);
  border-radius: 10px;
}

.file-item-copy {
  display: grid;
  min-width: 0;
  gap: 3px;
}

.file-item-name {
  overflow: hidden;
  color: var(--ink);
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-item-meta {
  color: var(--muted);
  font-size: 10px;
}

.file-item-actions {
  display: flex;
  flex: 0 0 auto;
  gap: 4px;
}

.file-item-button {
  padding: 5px 7px;
  color: var(--primary-deep);
  background: var(--primary-soft);
  border: 1px solid #dfe4ff;
  border-radius: 7px;
  font-size: 10px;
}

.file-item-button:hover:not(:disabled) {
  background: #e3e7ff;
}

.file-item-button-danger {
  color: var(--danger);
  background: #fff4f5;
  border-color: #f4d7da;
}

.file-item-button:disabled {
  cursor: not-allowed;
  opacity: 0.4;
}

.file-preview {
  display: block;
  width: 100%;
  min-height: 390px;
  margin-top: 12px;
  background: #eef1f7;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.extra-file-field,
.signature-pad {
  display: grid;
  gap: 9px;
  margin-top: 13px;
  padding: 12px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.extra-file-name {
  margin: 0;
  overflow: hidden;
  color: var(--muted);
  font-size: 11px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.signature-pad-canvas {
  display: block;
  width: 100%;
  aspect-ratio: 3 / 1;
  background: #fff;
  border: 1px dashed #b9c5df;
  border-radius: 10px;
  cursor: crosshair;
  touch-action: none;
}

.signature-pad-actions {
  display: flex;
  justify-content: flex-end;
}

.tool-controls {
  display: grid;
  gap: 10px;
  margin-top: 13px;
  padding: 12px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.tool-control-row {
  display: grid;
  grid-template-columns: minmax(88px, auto) minmax(0, 1fr);
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-size: 12px;
}

.tool-control-label-line {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  user-select: none;
  -webkit-user-select: none;
}

.tool-control-value {
  color: var(--primary-deep);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  font-weight: 750;
}

.tool-control-help {
  grid-column: 1 / -1;
  color: #9aa5b9;
  font-size: 10px;
  line-height: 1.5;
}

.tool-control-input {
  min-width: 0;
  accent-color: var(--primary);
}

.tool-control-input[type="text"],
.tool-control-input[type="number"] {
  cursor: text;
  user-select: text;
  -webkit-user-select: text;
}

select.tool-control-input {
  padding: 7px 9px;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
}

.tool-control-input[type="range"] {
  cursor: pointer;
}

.status-message {
  min-height: 20px;
  margin: 14px 2px 0;
  color: var(--muted);
  font-size: 12px;
}

.status-message.is-success {
  color: var(--success);
}

.status-message.is-error {
  color: var(--danger);
}

.seo-article {
  width: min(1160px, calc(100% - 48px));
  margin: 0 auto;
  padding: 27px 28px 30px;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(229, 234, 242, 0.9);
  border-radius: 22px;
}

.seo-article-heading {
  max-width: 700px;
}

.seo-article h2 {
  margin: 7px 0 8px;
  font-size: 22px;
  letter-spacing: -0.03em;
}

.seo-article-heading p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}

.seo-tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(165px, 1fr));
  gap: 10px;
  margin-top: 21px;
}

.seo-tool-more {
  margin-top: 14px;
  border-top: 1px solid var(--line);
}

.seo-tool-more summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 13px 2px;
  color: var(--primary-deep);
  cursor: pointer;
  list-style: none;
  font-size: 12px;
  font-weight: 750;
  user-select: none;
  -webkit-user-select: none;
}

.seo-tool-more summary::-webkit-details-marker {
  display: none;
}

.seo-tool-more summary::after {
  color: #9aa5b9;
  content: "+";
  font-size: 17px;
  font-weight: 400;
}

.seo-tool-more[open] summary::after {
  content: "−";
}

.seo-tool-grid-more {
  margin-top: 5px;
}

.seo-tool-card {
  display: grid;
  gap: 6px;
  min-height: 100px;
  padding: 14px;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  cursor: pointer;
  text-decoration: none;
  transition: border-color 160ms ease, box-shadow 160ms ease, transform 160ms ease;
  user-select: none;
  -webkit-user-select: none;
}

.seo-tool-card:hover {
  border-color: #c5cdfb;
  box-shadow: 0 8px 18px rgba(35, 54, 92, 0.07);
  transform: translateY(-2px);
}

.seo-tool-card strong {
  color: var(--primary-deep);
  font-size: 13px;
}

.seo-tool-card span {
  color: var(--muted);
  font-size: 11px;
  line-height: 1.55;
}

.seo-faq {
  max-width: 820px;
  margin-top: 27px;
}

.seo-faq h2 {
  font-size: 18px;
}

.seo-faq details {
  border-top: 1px solid var(--line);
}

.seo-faq details:last-child {
  border-bottom: 1px solid var(--line);
}

.seo-faq summary {
  padding: 13px 2px;
  color: var(--ink);
  cursor: pointer;
  font-size: 13px;
  font-weight: 700;
  user-select: none;
  -webkit-user-select: none;
}

.seo-faq p {
  margin: -3px 0 13px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.65;
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 18px 0 28px;
  color: #98a2b5;
  font-size: 11px;
}

.footer-dot {
  color: #c3cad7;
}

.footer-record-link {
  color: inherit;
  text-decoration: none;
}

.footer-record-link:hover {
  color: var(--primary);
}

@media (max-width: 820px) {
  .site-header,
  .main-layout,
  .site-footer,
  .seo-article {
    width: min(100% - 32px, 680px);
  }

  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 13px;
    padding: 28px 0 24px;
  }

  .main-layout {
    display: block;
    padding-bottom: 28px;
  }

  .sidebar {
    margin-bottom: 22px;
  }

  .tool-nav > .tool-nav-section:first-child {
    display: none;
  }

  .tool-nav-categories {
    max-height: 100px;
    overflow-y: auto;
    overscroll-behavior: contain;
    scrollbar-gutter: stable;
  }

  .tool-nav-list-popular {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .seo-tool-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .workspace {
    padding-top: 0;
  }
}

@media (max-width: 620px) {
  .tool-card {
    padding: 15px;
    border-radius: 18px;
  }

  .tool-toolbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .editor-grid {
    grid-template-columns: 1fr;
  }

  .editor-area {
    min-height: 220px;
  }

  .site-footer {
    line-height: 1.6;
    text-align: center;
  }

  .seo-article {
    padding: 21px 17px 24px;
    border-radius: 18px;
  }

  .seo-tool-grid {
    grid-template-columns: 1fr;
  }
}