:root {
  color-scheme: light dark;
  --bg: #f4f5f7;
  --panel: #ffffff;
  --text: #1c1e21;
  --muted: #666a70;
  --accent: #2f6fed;
  --accent-text: #ffffff;
  --key-bg: #ffffff;
  --key-border: #c7cad1;
  --key-active: #2f6fed;
  --key-shadow: rgba(0, 0, 0, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16171a;
    --panel: #212226;
    --text: #eceef1;
    --muted: #9aa0a8;
    --accent: #5b8cff;
    --accent-text: #0b0d10;
    --key-bg: #2b2d31;
    --key-border: #3d4046;
    --key-active: #5b8cff;
    --key-shadow: rgba(0, 0, 0, 0.4);
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 16px;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;
}

.site-header {
  max-width: 900px;
  margin: 0 auto 20px;
}

.site-header h1 {
  margin: 0 0 6px;
  font-size: 1.6rem;
}

.subtitle {
  color: var(--muted);
  margin: 0 0 12px;
  line-height: 1.4;
}

.subtitle a {
  color: var(--accent);
}

.header-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.editor-link,
.btn {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
  border: 1px solid var(--key-border);
  cursor: pointer;
}

.editor-link {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}

.preview {
  max-width: 900px;
  margin: 0 auto 20px;
}

.intro-summary {
  max-width: 900px;
  margin: 0 auto 20px;
  background: var(--panel);
  border: 1px solid var(--key-border);
  border-radius: 10px;
  padding: 16px 18px;
  line-height: 1.6;
}

.intro-summary p {
  margin: 0 0 10px;
}

.intro-summary p:last-of-type {
  margin-bottom: 0;
}

.intro-summary ul {
  margin: 10px 0 0;
  padding-left: 20px;
}

.intro-summary li {
  margin-bottom: 6px;
}

.intro-summary a {
  color: var(--accent);
}

.preview-label {
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.preview-box {
  background: var(--panel);
  border: 1px solid var(--key-border);
  border-radius: 10px;
  padding: 14px 16px;
  min-height: 60px;
  max-height: 220px;
  overflow-y: auto;
  white-space: pre-wrap;
  word-wrap: break-word;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.95rem;
}

.placeholder {
  color: var(--muted);
  font-style: italic;
}

main {
  max-width: 900px;
  margin: 0 auto;
}

.prose {
  max-width: 680px;
  margin: 0 auto;
  background: var(--panel);
  border: 1px solid var(--key-border);
  border-radius: 12px;
  padding: 20px 24px;
}

.prose h2 {
  font-size: 1.15rem;
  margin: 28px 0 10px;
}

.prose h2:first-child {
  margin-top: 0;
}

.prose p {
  line-height: 1.6;
  margin: 0 0 14px;
}

.prose ul {
  margin: 0 0 14px;
  padding-left: 22px;
}

.prose li {
  line-height: 1.6;
  margin-bottom: 4px;
}

.prose strong {
  color: var(--text);
}

.flow-diagram {
  background: var(--bg);
  border: 1px solid var(--key-border);
  border-radius: 10px;
  padding: 14px 16px;
  margin: 0 0 14px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.9rem;
  line-height: 1.7;
  text-align: center;
  white-space: pre-wrap;
  color: var(--muted);
}

.keyboard {
  background: var(--panel);
  border: 1px solid var(--key-border);
  border-radius: 12px;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.kb-row {
  display: flex;
  gap: 6px;
  justify-content: center;
  flex-wrap: wrap;
}

.key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 38px;
  height: 44px;
  padding: 0 10px;
  background: var(--key-bg);
  border: 1px solid var(--key-border);
  border-radius: 8px;
  color: var(--text);
  text-decoration: none;
  font-size: 1rem;
  box-shadow: 0 2px 0 var(--key-shadow);
  user-select: none;
  transition: transform 0.05s ease, background 0.1s ease;
}

.key:active {
  transform: translateY(2px);
  box-shadow: none;
}

.key-action {
  font-size: 0.8rem;
  padding: 0 12px;
  color: var(--muted);
}

.key-space {
  flex: 1 1 auto;
  max-width: 420px;
}

.key-wide {
  flex-grow: 1;
}

.key-backspace,
.key-tab,
.key-enter,
.key-caps,
.key-shift,
.key-clear {
  min-width: 70px;
}

.key-active {
  background: var(--key-active);
  color: var(--accent-text);
  border-color: var(--key-active);
}

.site-footer {
  max-width: 900px;
  margin: 24px auto 0;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.4;
}

.site-footer a {
  color: var(--accent);
}

.editor-main {
  max-width: 900px;
  margin: 0 auto;
}

.editor-surface {
  display: flex;
  align-items: stretch;
  border: 1px solid var(--key-border);
  border-radius: 10px;
  overflow: hidden;
  background: var(--panel);
}

.gutter {
  flex: 0 0 auto;
  width: 140px;
  max-width: 35vw;
  overflow: hidden;
  border-right: 1px solid var(--key-border);
  background: var(--bg);
  padding: 14px 0;
  box-sizing: border-box;
}

.gutter-row {
  height: 24px;
  line-height: 24px;
  padding: 0 8px;
  display: flex;
  align-items: center;
  gap: 4px;
  white-space: nowrap;
  overflow: hidden;
}

.uid-badge {
  display: inline-block;
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  background: hsl(var(--hue) 70% 88%);
  color: hsl(var(--hue) 70% 25%);
  flex: 0 0 auto;
}

@media (prefers-color-scheme: dark) {
  .uid-badge {
    background: hsl(var(--hue) 55% 22%);
    color: hsl(var(--hue) 70% 78%);
  }
}

:root[data-theme="dark"] .uid-badge {
  background: hsl(var(--hue) 55% 22%);
  color: hsl(var(--hue) 70% 78%);
}

.uid-more {
  color: var(--muted);
  font-size: 0.7rem;
  flex: 0 0 auto;
}

.your-tag {
  margin: 0 0 12px;
  font-size: 0.9rem;
  color: var(--muted);
}

.flow-hint {
  display: block;
  font-size: 0.78rem;
  margin-top: 2px;
  opacity: 0.85;
}

#editor-text {
  flex: 1 1 auto;
  width: 100%;
  background: var(--panel);
  color: var(--text);
  border: none;
  border-radius: 0;
  padding: 14px 16px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 1rem;
  line-height: 24px;
  white-space: pre;
  overflow: auto;
  resize: vertical;
  box-sizing: border-box;
}

.editor-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: 10px;
  flex-wrap: wrap;
}

.editor-buttons {
  display: flex;
  gap: 8px;
}

.status {
  color: var(--muted);
  font-size: 0.85rem;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}

.btn-secondary {
  background: var(--key-bg);
  color: var(--text);
}

.hist-list {
  list-style: none;
  margin: 0;
  padding: 0;
  background: var(--panel);
  border: 1px solid var(--key-border);
  border-radius: 10px;
  overflow: hidden;
}

.hist-item {
  padding: 10px 14px;
  border-bottom: 1px solid var(--key-border);
  font-size: 0.92rem;
  line-height: 1.5;
  word-wrap: break-word;
}

.hist-item:last-child {
  border-bottom: none;
}

.hist-item.placeholder {
  color: var(--muted);
  font-style: italic;
}

.hist-time {
  color: var(--muted);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.85rem;
  margin-right: 4px;
}

.hist-insert {
  color: #1a8f4c;
  font-weight: 600;
}

.hist-delete {
  color: #d1453b;
  font-weight: 600;
}

.hist-iptag {
  color: var(--muted);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.78rem;
}

@media (max-width: 500px) {
  .key {
    min-width: 30px;
    height: 38px;
    font-size: 0.85rem;
    padding: 0 6px;
  }

  .gutter {
    width: 88px;
  }

  .uid-badge {
    font-size: 0.6rem;
    padding: 1px 4px;
  }
}