:root {
  color-scheme: light;
  --bg: #f6f8fa;
  --surface: #ffffff;
  --surface-2: #f6f8fa;
  --text: #24292f;
  --muted: #57606a;
  --primary: #0969da;
  --primary-2: #0969da;
  --success: #1a7f37;
  --warning: #bf8700;
  --border: #d0d7de;
  --shadow: 0 1px 0 rgba(31,35,40,0.04);
  --input-bg: #ffffff;
  --input-text: #24292f;
  --focus: #0969da;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #1f2630;
  --text: #c9d1d9;
  --muted: #8b949e;
  --primary: #58a6ff;
  --primary-2: #58a6ff;
  --success: #3fb950;
  --warning: #d29922;
  --border: #30363d;
  --shadow: 0 8px 24px rgba(1,4,9,.24);
  --input-bg: #0d1117;
  --input-text: #c9d1d9;
  --focus: #58a6ff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif,Apple Color Emoji,Segoe UI Emoji;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  transition: background .2s ease, color .2s ease;
}
a { color: var(--primary-2); text-decoration: none; }
a:hover { color: var(--primary); text-decoration: underline; text-underline-offset: 2px; }
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
img { max-width: 100%; }
.container { width: min(1160px, calc(100% - 2rem)); margin: 0 auto; }
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.navbar {
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  padding: .95rem 0;
}
.brand { display: inline-flex; align-items: center; gap: .6rem; font-weight: 600; font-size: 1rem; color: var(--text); text-transform: none; }
.brand:hover { color: var(--primary); text-decoration: none; }
.brand-mark { display: inline-grid; place-items: center; width: 2.15rem; height: 2.15rem; border-radius: .8rem; background: color-mix(in srgb, var(--surface-2) 82%, transparent); color: var(--text); border: 1px solid var(--border); transition: background-color .15s ease, border-color .15s ease, color .15s ease, transform .15s ease; flex: 0 0 auto; }
.brand-mark svg { width: 1.1rem; height: 1.1rem; display: block; }
.brand-wordmark { display: inline-flex; align-items: center; height: 18px; flex: 0 1 auto; }
.brand-wordmark img { display: none; height: 100%; width: auto; max-width: min(100%, 160px); }
:root[data-theme="dark"] .brand-wordmark-dark-theme,
body[data-theme="dark"] .brand-wordmark-dark-theme,
:root[data-theme="light"] .brand-wordmark-light-theme,
body[data-theme="light"] .brand-wordmark-light-theme { display: block; }
.brand:hover .brand-mark { background: color-mix(in srgb, var(--surface-2) 90%, var(--primary) 10%); border-color: color-mix(in srgb, var(--border) 78%, var(--primary) 22%); color: var(--primary); transform: translateY(-1px); }
.nav-links { display: flex; gap: 1rem; flex-wrap: wrap; }
.nav-links a { color: var(--muted); font-weight: 600; }
.nav-links a:hover { color: var(--primary); text-decoration: none; }
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  padding: 0;
  border-radius: 6px;
  cursor: pointer;
  min-width: 32px;
  transition: background-color .15s ease, border-color .15s ease;
}
.theme-toggle:hover { background: var(--surface-2); border-color: color-mix(in srgb, var(--border) 70%, var(--primary) 30%); }
.theme-toggle svg {
  width: 16px;
  height: 16px;
  display: block;
  transform-origin: center;
  transition: transform .2s ease;
}
.theme-toggle:hover svg,
.theme-toggle:focus-visible svg {
  transform: rotate(-10deg) scale(1.06);
}

@media (prefers-reduced-motion: reduce) {
  .theme-toggle,
  .theme-toggle svg {
    transition: none;
  }

  .theme-toggle:hover svg,
  .theme-toggle:focus-visible svg {
    transform: none;
  }
}
.hero { padding: 4.5rem 0 3rem; display: grid; gap: 1.25rem; }
.hero-grid { display: grid; grid-template-columns: 1.2fr .8fr; gap: 2rem; align-items: center; }
.hero h1 { font-size: clamp(2rem, 3vw, 3.2rem); line-height: 1.1; margin: 0; }
.hero p { font-size: 1.05rem; color: var(--muted); margin: 0; max-width: 680px; }
.hero-card, .card, .tool-card { background: var(--surface); border: 1px solid var(--border); border-radius: 22px; box-shadow: var(--shadow); }
.hero-card { padding: 1.25rem; }
.hero-card ul { margin: .35rem 0 0 1rem; color: var(--muted); }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 32px;
  padding: 0 12px;
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
  font-size: .875rem;
  font-weight: 500;
  border: 1px solid var(--border);
  box-shadow: none;
  line-height: 20px;
  cursor: pointer;
  transition: background-color .15s ease, border-color .15s ease, color .15s ease;
}

.btn:hover {
  background: var(--surface-2);
  border-color: color-mix(in srgb, var(--border) 72%, var(--primary) 28%);
}

.btn.primary {
  background: var(--primary);
  border-color: color-mix(in srgb, var(--primary) 84%, black 16%);
  color: #ffffff;
  box-shadow: none;
}

.btn.primary:hover {
  background: color-mix(in srgb, var(--primary) 90%, black 10%);
  border-color: color-mix(in srgb, var(--primary) 80%, black 20%);
}

.btn.secondary {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  box-shadow: none;
}

.btn.secondary:hover {
  background: var(--surface-2);
}

.btn:active {
  transform: translateY(0);
}
.section-title { display: flex; justify-content: space-between; gap: 1rem; align-items: center; margin: 2rem 0 1rem; }
.section-title h2 { margin: 0; font-size: 1.3rem; }
.section-title p { margin: 0; color: var(--muted); }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; }
.tool-card { padding: 1rem; transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease; }
.tool-card:hover { transform: translateY(-2px); border-color: color-mix(in srgb, var(--primary) 35%, var(--border) 65%); box-shadow: 0 8px 24px rgba(31,35,40,0.08); }
.tool-card h3 { margin: .15rem 0 .35rem; font-size: 1.05rem; }
.tool-card p { color: var(--muted); margin: 0 0 .75rem; font-size: .95rem; }
.page-shell { padding: 2rem 0 4rem; }
.page-hero { padding: 3rem 0 2rem; }
.page-hero p { color: var(--muted); max-width: 720px; }
.page-hero h1 { margin: 0 0 .5rem; font-size: clamp(1.8rem, 2.5vw, 2.6rem); }
.content-grid { display: grid; grid-template-columns: 1.2fr .8fr; gap: 1.25rem; }
.card { padding: 1.25rem; }
.card h2, .card h3 { margin-top: 0; }
.card ul { color: var(--muted); }
.tool-panel { display: flex; flex-direction: column; gap: 0; }
.tool-panel .label { display: block; line-height: 1.1; margin: 0 0 .1rem; }
.tool-panel textarea { margin: 0; }
.tool-panel .actions { margin-top: .65rem; }
.tool-panel .result { margin-top: .4rem; }
.tool-panel .actions + .result-grid { margin-top: .4rem; }
.tool-panel .result-grid .result { margin-top: 0; }
.tool-panel .date-field-group {
  display: grid;
  gap: .35rem;
}
.tool-panel .duration-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: .6rem;
}
.tool-panel [hidden] {
  display: none !important;
}
.tool-panel .quick-insert-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: .45rem;
}
.tool-panel .quick-insert-grid .btn {
  min-width: 0;
  padding: .5rem .6rem;
}
.tool-panel > .dynamic-tool {
  display: grid;
  gap: .625rem;
}
.tool-panel > .dynamic-tool .label,
.tool-panel > .dynamic-tool textarea,
.tool-panel > .dynamic-tool .actions,
.tool-panel > .dynamic-tool .result,
.tool-panel > .dynamic-tool .actions + .result,
.tool-panel > .dynamic-tool .actions + .result-grid {
  margin-top: 0;
  margin-bottom: 0;
}
.tool-panel.tool-panel-tight { display: block; }
.tool-panel.tool-panel-tight .actions { margin: 0; gap: .5rem; }
.tool-panel.tool-panel-tight .result { margin-top: .25rem; min-height: 80px; padding: .75rem; }
.label { font-weight: 700; font-size: .95rem; }
.tool-panel .label { margin: 0; }
input, textarea, select { width: 100%; padding: .9rem 1rem; background: var(--input-bg); color: var(--input-text); border: 1px solid var(--border); border-radius: 6px; font: inherit; }
textarea { min-height: 180px; resize: vertical; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: .75rem; }
.tool-panel .actions .btn { min-width: 88px; }
.tool-panel .actions .icon-btn {
  min-width: 32px;
  width: 32px;
  height: 32px;
  justify-content: center;
  padding: 0;
}
.tool-panel .actions + .result { margin-top: .4rem; }
.tool-panel.tool-panel-tight .actions + .result { margin-top: .25rem; }
.result > [data-result-text] {
  display: block;
}
.copy-action {
  position: relative;
  display: inline-flex;
  align-items: center;
  margin-left: auto;
}
.two-column-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .75rem;
}
.two-column-grid > div {
  min-width: 0;
}
.result { padding: 1rem; border-radius: 14px; background: color-mix(in srgb, var(--primary) 10%, transparent); border: 1px solid color-mix(in srgb, var(--primary) 20%, transparent); white-space: pre-wrap; word-break: break-word; min-height: 80px; color: var(--text); }
.result.success { border-color: color-mix(in srgb, var(--success) 24%, transparent); }
.result.error { border-color: color-mix(in srgb, var(--warning) 24%, transparent); }
.result.warning { border-color: color-mix(in srgb, var(--warning) 26%, transparent); }
.result.warning {
  background: color-mix(in srgb, var(--warning) 12%, transparent);
}
.inline-check-row {
  display: flex;
  align-items: center;
  gap: .55rem;
  margin: .2rem 0 .7rem;
}
.inline-check-row .label {
  margin: 0;
  font-weight: 600;
}
.inline-check-row input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  margin: 0;
  flex: 0 0 auto;
}
.strength-meter {
  display: grid;
  gap: .35rem;
  margin-top: .25rem;
}
.strength-meter-track {
  width: 100%;
  height: 10px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
}
.strength-meter-fill {
  height: 100%;
  width: 0;
  border-radius: inherit;
  transition: width .2s ease, background-color .2s ease;
  background: color-mix(in srgb, var(--warning) 60%, var(--surface) 40%);
}
.strength-meter-fill[data-state="weak"] {
  background: color-mix(in srgb, #d73a49 70%, var(--surface) 30%);
}
.strength-meter-fill[data-state="moderate"] {
  background: color-mix(in srgb, var(--warning) 78%, var(--surface) 22%);
}
.strength-meter-fill[data-state="strong"] {
  background: color-mix(in srgb, var(--success) 80%, var(--surface) 20%);
}
.strength-meter-label {
  font-size: .88rem;
  color: var(--muted);
}
.copy-popbox {
  position: absolute;
  left: 50%;
  top: calc(100% + .5rem);
  transform: translateX(-50%);
  display: inline-flex;
  align-items: center;
  padding: .32rem .6rem;
  border-radius: .55rem;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface-2) 92%, transparent);
  color: var(--text);
  font-size: .82rem;
  font-weight: 700;
  box-shadow: 0 10px 25px rgba(0, 0, 0, .1);
  white-space: nowrap;
  z-index: 2;
  pointer-events: none;
}
.copy-popbox::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: 100%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-bottom-color: color-mix(in srgb, var(--surface-2) 92%, transparent);
}
.copy-popbox[data-state="success"] {
  border-color: color-mix(in srgb, var(--success) 24%, var(--border));
  background: color-mix(in srgb, var(--success) 14%, var(--surface));
}
.copy-popbox[data-state="success"]::after {
  border-bottom-color: color-mix(in srgb, var(--success) 14%, var(--surface));
}
.copy-popbox[data-state="error"] {
  border-color: color-mix(in srgb, var(--warning) 24%, var(--border));
  background: color-mix(in srgb, var(--warning) 14%, var(--surface));
}
.copy-popbox[data-state="error"]::after {
  border-bottom-color: color-mix(in srgb, var(--warning) 14%, var(--surface));
}
.tool-panel .inline-check-row + .actions,
.tool-panel .two-column-grid + .inline-check-row {
  margin-top: .15rem;
}
.result-grid { display: grid; gap: .8rem; }
.fixed-result-panel > .result {
  height: 180px;
  overflow: auto;
}
.markdown-preview-panel .result {
  white-space: normal;
}
.markdown-preview-panel .result h1,
.markdown-preview-panel .result h2,
.markdown-preview-panel .result h3,
.markdown-preview-panel .result p,
.markdown-preview-panel .result ul {
  margin: 0 0 .5rem;
}
.markdown-preview-panel .result ul {
  padding-left: 1.2rem;
}
.markdown-preview-panel .result > :last-child {
  margin-bottom: 0;
}
.diff-input-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .9rem;
}
.diff-input-pane {
  min-width: 0;
}
.tool-panel .diff-input-pane .label {
  display: block;
  line-height: 1.2;
  margin: 0 0 .55rem;
}
@media (max-width: 600px) {
  .tool-panel .duration-grid {
    grid-template-columns: 1fr;
  }
  .tool-panel .quick-insert-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}
.diff-output-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .9rem; margin-top: .4rem; }
.diff-textarea {
  min-height: 460px;
  height: 460px;
  overflow: auto;
  resize: vertical;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.diff-inline-view {
  min-height: 460px;
  height: 460px;
}
.diff-input-pane .diff-lines {
  max-height: none;
}
.diff-summary {
  padding: .7rem .9rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface-2) 55%, transparent);
  font-size: .92rem;
}
.diff-summary.success {
  border-color: color-mix(in srgb, var(--success) 35%, transparent);
  background: color-mix(in srgb, var(--success) 12%, transparent);
}
.diff-summary.error {
  border-color: color-mix(in srgb, var(--warning) 35%, transparent);
  background: color-mix(in srgb, var(--warning) 10%, transparent);
}
.diff-lines {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  overflow: auto;
  max-height: 480px;
  min-height: 300px;
}
.diff-line {
  display: grid;
  grid-template-columns: 2.6rem 1.3rem minmax(0, 1fr);
  gap: .4rem;
  padding: .28rem .5rem;
  border-bottom: 1px solid color-mix(in srgb, var(--border) 80%, transparent);
  font-family: Consolas, Menlo, Monaco, monospace;
  font-size: .85rem;
  line-height: 1.35;
}
.diff-line:last-child { border-bottom: 0; }
.diff-line-number { color: var(--muted); text-align: right; }
.diff-line-mark { font-weight: 700; color: var(--muted); text-align: center; }
.diff-line-text {
  min-width: 0;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.diff-line.added {
  background: color-mix(in srgb, var(--success) 18%, transparent);
  border-left: 3px solid color-mix(in srgb, var(--success) 65%, transparent);
}
.diff-line.added .diff-line-mark { color: var(--success); }
.diff-line.removed {
  background: color-mix(in srgb, var(--warning) 20%, transparent);
  border-left: 3px solid color-mix(in srgb, var(--warning) 70%, transparent);
}
.diff-line.removed .diff-line-mark { color: var(--warning); }
.diff-line.empty { background: color-mix(in srgb, var(--surface-2) 55%, transparent); }
.faq-list { display: grid; gap: .75rem; }
.faq-item { padding: .95rem 1rem; border-radius: 16px; background: color-mix(in srgb, var(--surface-2) 55%, transparent); border: 1px solid var(--border); }
.faq-item strong { display: block; margin-bottom: .25rem; }
.related-list { display: flex; flex-wrap: wrap; gap: .65rem; }
.related-list a { padding: .45rem .7rem; border-radius: 999px; border: 1px solid var(--border); background: var(--surface); color: var(--text); }
.related-list a:hover { background: var(--surface-2); text-decoration: none; }
.footer { padding: 2rem 0 3rem; color: var(--muted); text-align: center; }
.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: .9rem 1.1rem;
  margin-bottom: .4rem;
  font-size: .9rem;
}
.footer-links a {
  color: var(--muted);
}
.footer-links a:hover {
  color: var(--primary);
  text-decoration: none;
}
.footer-copy {
  color: var(--muted);
  font-size: .92rem;
}
.muted { color: var(--muted); }
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: .75rem; }
.stat { padding: 1rem; border-radius: 16px; background: var(--surface); border: 1px solid var(--border); }
.stat strong { display: block; font-size: 1.2rem; }
@media (max-width: 860px) {
  .hero-grid, .content-grid, .diff-input-grid, .diff-output-grid { grid-template-columns: 1fr; }
  .navbar { flex-wrap: wrap; }
  .nav-links { gap: .75rem; }
}