:root {
  --bg: #f4f6fb;
  --surface: rgba(255, 255, 255, 0.9);
  --surface-strong: #ffffff;
  --text: #17243b;
  --text-muted: #5e6d85;
  --border: #d9e2f0;
  --border-strong: #c3d0e6;
  --primary: #1767ff;
  --primary-soft: rgba(23, 103, 255, 0.12);
  --ok-soft: rgba(25, 135, 84, 0.12);
  --warn-soft: rgba(245, 158, 11, 0.14);
  --shadow: 0 18px 48px rgba(15, 23, 42, 0.08);
  --radius: 18px;
  --app-shell-max: 1240px;
  --rail-divider-color: #dce5f2;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  background:
    radial-gradient(circle at top left, rgba(23, 103, 255, 0.1), transparent 34%),
    radial-gradient(circle at top right, rgba(56, 189, 248, 0.12), transparent 28%),
    linear-gradient(180deg, #f8fbff 0%, #f4f6fb 38%, #eef3fa 100%);
  color: var(--text);
  font-family: "Segoe UI", "Noto Sans", sans-serif;
}

body {
  line-height: 1.5;
}

button,
input,
select,
textarea {
  font: inherit;
}

a {
  color: #2157b3;
}

h1,
h2,
h3,
p,
ul,
pre {
  margin: 0;
}

.layout {
  margin: 1rem auto 0;
  display: grid;
  gap: 1rem;
}

.panel {
  border: 1px solid var(--border);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow);
  padding: 1rem;
}

.intro-panel {
  display: grid;
  gap: 1rem;
}

.card {
  border: 1px solid rgba(217, 226, 240, 0.92);
  border-radius: var(--radius);
  background: var(--surface);
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
}

.panel-head {
  display: flex;
  gap: 1rem;
}

.panel-head--split {
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
}

.section-intro {
  display: grid;
  gap: 0.35rem;
}

.subtle {
  color: var(--text-muted);
}

.mono {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #f7fbff;
  color: var(--text-muted);
  font-size: 0.86rem;
  font-weight: 700;
}

.badge--ok {
  background: #eff9f2;
  border-color: #cfe6d9;
  color: #147046;
}

.help-panel {
  border: 1px solid var(--border);
  border-radius: 18px;
  background: rgba(246, 250, 255, 0.9);
}

.help-panel summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  padding: 1rem;
  font-weight: 700;
}

.help-panel summary::-webkit-details-marker {
  display: none;
}

.help-body {
  display: grid;
  gap: 0.9rem;
  padding: 0 1rem 1rem;
}

.help-grid {
  display: grid;
  gap: 0.85rem;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.help-card {
  border: 1px solid var(--border);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.9);
  padding: 0.95rem;
}

.help-card strong {
  display: block;
  margin-bottom: 0.35rem;
}

.workspace-panel {
  display: grid;
  gap: 1rem;
}

.toolbar {
  position: sticky;
  top: 12px;
  z-index: 20;
  display: grid;
  gap: 1rem;
  padding: 1rem;
}

.toolbar-row {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
}

.toolbar-row--presets {
  display: grid;
  gap: 0.8rem;
}

.toolbar-presets-head {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
}

.toolbar-row--controls {
  align-items: center;
}

.toolbar-label-group {
  display: grid;
  gap: 0.25rem;
}

.preset-grid {
  display: grid;
  min-width: 1020px;
  width: 100%;
  gap: 0.7rem;
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.preset-grid-wrap {
  width: 100%;
  overflow-x: auto;
  padding-bottom: 0.2rem;
}

.preset-card {
  appearance: none;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.92);
  padding: 0.9rem;
  text-align: left;
  cursor: pointer;
  display: grid;
  gap: 0.35rem;
  transition: border-color 140ms ease, box-shadow 140ms ease, transform 140ms ease, background 140ms ease;
}

.preset-card strong {
  display: block;
  font-size: 0.98rem;
  line-height: 1.35;
}

.preset-card .subtle {
  font-size: 0.84rem;
  line-height: 1.45;
}

.preset-card:hover,
.preset-card:focus-visible {
  border-color: rgba(23, 103, 255, 0.38);
  box-shadow: 0 10px 24px rgba(23, 103, 255, 0.12);
}

.preset-card.is-active {
  border-color: rgba(23, 103, 255, 0.45);
  background: linear-gradient(180deg, rgba(237, 244, 255, 0.98), rgba(255, 255, 255, 0.94));
  box-shadow: 0 14px 30px rgba(23, 103, 255, 0.14);
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  min-height: 42px;
  font-weight: 600;
}

.toolbar-actions,
.editor-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.94);
  color: var(--text);
  border-radius: 12px;
  padding: 0.7rem 0.95rem;
  font-weight: 650;
  cursor: pointer;
  transition: background 120ms ease, border-color 120ms ease, transform 120ms ease;
}

.btn:hover,
.btn:focus-visible {
  background: var(--surface-strong);
  border-color: var(--border-strong);
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  border-color: transparent;
  background: linear-gradient(180deg, #4d8aff, var(--primary));
  color: #ffffff;
  box-shadow: 0 12px 24px rgba(23, 103, 255, 0.24);
}

.btn-primary:hover,
.btn-primary:focus-visible,
.btn-primary:active {
  background: linear-gradient(180deg, #4d8aff, var(--primary));
  border-color: transparent;
  color: #ffffff;
}

.btn-small {
  padding: 0.5rem 0.72rem;
  border-radius: 10px;
  font-size: 0.9rem;
}

.status-note {
  border-radius: 14px;
  padding: 0.8rem 0.95rem;
  background: rgba(248, 250, 255, 0.95);
  color: var(--text-muted);
}

.status-note.is-success {
  background: rgba(236, 252, 243, 0.95);
  color: #147046;
}

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

.editor-card {
  display: grid;
  gap: 0.8rem;
  padding: 1rem;
}

.editor-card--output {
  background: linear-gradient(180deg, rgba(244, 248, 255, 0.92), rgba(255, 255, 255, 0.94));
}

.editor-head {
  display: flex;
  gap: 0.75rem;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
}

textarea {
  width: 100%;
  min-height: 360px;
  resize: vertical;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1rem;
  background: #ffffff;
  color: var(--text);
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  line-height: 1.55;
}

textarea:focus-visible,
select:focus-visible,
input:focus-visible,
button:focus-visible {
  outline: 2px solid rgba(23, 103, 255, 0.38);
  outline-offset: 2px;
}

.editor-foot {
  font-size: 0.93rem;
}

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

.insight-card {
  padding: 1rem;
  display: grid;
  gap: 0.85rem;
}

.stats-grid {
  display: grid;
  gap: 0.7rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.stat-chip {
  border: 1px solid var(--border);
  border-radius: 14px;
  background: rgba(250, 252, 255, 0.94);
  padding: 0.8rem;
  display: grid;
  gap: 0.25rem;
}

.stat-chip strong {
  font-size: 1.05rem;
}

.warning-list {
  display: grid;
  gap: 0.6rem;
  padding-left: 1.1rem;
  color: var(--text-muted);
}

.warning-list li {
  line-height: 1.5;
}

.advanced-panel {
  padding: 0;
  overflow: hidden;
}

.advanced-panel summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  padding: 1rem;
  font-weight: 700;
}

.advanced-panel summary::-webkit-details-marker {
  display: none;
}

.advanced-grid {
  display: grid;
  gap: 1rem;
  padding: 0 1rem 1rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.option-group {
  margin: 0;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: rgba(250, 252, 255, 0.92);
  padding: 1rem;
  display: grid;
  gap: 0.7rem;
}

.option-group legend {
  padding: 0 0.35rem;
  font-weight: 700;
}

.option-field {
  display: grid;
  gap: 0.35rem;
}

.option-field input,
.option-field select {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #ffffff;
  color: var(--text);
  padding: 0.72rem 0.82rem;
}

.checkbox-row {
  display: flex;
  gap: 0.7rem;
  align-items: center;
  min-height: 36px;
}

.checkbox-row input {
  width: 16px;
  height: 16px;
}

.guide-layout {
  margin: 1rem auto 0;
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.guide-card {
  border: 1px solid var(--border);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow);
  padding: 1rem;
  display: grid;
  gap: 0.8rem;
}

.guide-card ul {
  padding-left: 1.1rem;
  color: var(--text-muted);
}

.example-compare {
  display: grid;
  gap: 0.85rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.example-compare pre {
  white-space: pre-wrap;
  word-break: break-word;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: rgba(248, 251, 255, 0.94);
  padding: 0.9rem;
  min-height: 160px;
  color: var(--text);
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
}

.preset-name {
  font-size: 1.05rem;
  font-weight: 700;
}

.faq-stack {
  display: grid;
  gap: 0.7rem;
}

.faq-stack details {
  border: 1px solid var(--border);
  border-radius: 14px;
  background: rgba(248, 251, 255, 0.92);
  padding: 0.85rem 0.9rem;
}

.faq-stack summary {
  cursor: pointer;
  font-weight: 700;
}

.faq-stack p {
  margin-top: 0.65rem;
  color: var(--text-muted);
}

.updated-at {
  font-size: 0.92rem;
  color: var(--text-muted);
}

.tool-footer {
  margin-top: 2rem;
  padding-bottom: 1rem;
}

.tool-footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 1rem;
  margin-bottom: 0.9rem;
}

.tool-footer__nav a {
  color: inherit;
  text-decoration: none;
}

.tool-footer__nav a:hover,
.tool-footer__nav a:focus-visible {
  text-decoration: underline;
}

.tool-footer__meta,
.tool-footer__note {
  margin: 0 0 0.7rem;
  color: #4c5d74;
  line-height: 1.6;
}

.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;
}

@media (max-width: 1080px) {
  .editor-grid,
  .insights-grid,
  .guide-layout,
  .advanced-grid {
    grid-template-columns: 1fr;
  }

  .help-grid,
  .example-compare {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 760px) {
  .panel,
  .guide-card,
  .toolbar,
  .editor-card,
  .insight-card,
  .help-panel summary,
  .help-body,
  .advanced-panel summary,
  .advanced-grid {
    padding-left: 0.9rem;
    padding-right: 0.9rem;
  }

  .toolbar {
    top: 8px;
  }

  .panel-head--split,
  .toolbar-presets-head,
  .editor-head,
  .toolbar-row,
  .help-panel summary,
  .advanced-panel summary {
    flex-direction: column;
    align-items: flex-start;
  }

  .preset-grid {
    min-width: 920px;
  }

  .preset-grid {
    width: 100%;
  }

  textarea {
    min-height: 280px;
  }
}