:root {
  --bg: #ffffff;
  --secondary: #f6f8fa;
  --border: #d0d7de;
  --text: #1f2328;
  --text-secondary: #656d76;
  --accent: #0969da;
  --green: #1a7f37;
  --red: #cf222e;
  --yellow: #9a6700;
  --radius: 6px;
  --shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --secondary: #161b22;
    --border: #30363d;
    --text: #c9d1d9;
    --text-secondary: #8b949e;
    --accent: #58a6ff;
    --green: #3fb950;
    --red: #f85149;
    --yellow: #d29922;
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

/* ── Topbar ── */
.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 52px;
  padding: 0 20px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}

.topbar-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 15px;
  color: var(--text);
  text-decoration: none;
}

.topbar-links {
  display: flex;
  align-items: center;
  gap: 16px;
}

.topbar-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
}

.topbar-links a:hover {
  color: var(--text);
}

/* ── Layout ── */
.layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  min-height: calc(100vh - 52px);
}

.sidebar {
  border-right: 1px solid var(--border);
  padding: 16px 0;
  background: var(--secondary);
  overflow-y: auto;
}

.sidebar-section {
  padding: 8px 16px 4px;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
}

.sidebar-item {
  display: block;
  padding: 6px 16px;
  font-size: 13px;
  color: var(--text);
  text-decoration: none;
  cursor: pointer;
  border-radius: 0;
}

.sidebar-item:hover {
  background: var(--border);
}

.sidebar-item.active {
  background: var(--accent);
  color: #fff;
}

.main {
  padding: 24px 32px;
  overflow-y: auto;
}

.main h1 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 4px;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 24px;
}

/* ── Presets ── */
.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 20px;
}

.preset-btn {
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 500;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
  transition: all 0.15s;
}

.preset-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.preset-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ── Builder fields ── */
.builder {
  background: var(--secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}

.field-row {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.field-row:last-child {
  border-bottom: none;
}

.field-label {
  min-width: 100px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  padding-top: 6px;
}

.field-input {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.field-input select,
.field-input input {
  padding: 6px 10px;
  font-size: 13px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
  font-family: inherit;
}

.field-input select:focus,
.field-input input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(9,105,218,0.15);
}

/* ── Expression output ── */
.expr-output {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.expr-string {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
  font-size: 18px;
  font-weight: 600;
  color: var(--accent);
  background: var(--bg);
  padding: 8px 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.copy-btn {
  padding: 6px 12px;
  font-size: 12px;
  font-weight: 500;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
}

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

.copy-btn.copied {
  color: var(--green);
  border-color: var(--green);
}

/* ── Human readable ── */
.human-readable {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

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

/* ── Timezone ── */
.tz-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-size: 13px;
}

.tz-row label {
  color: var(--text-secondary);
}

.tz-row select {
  padding: 4px 8px;
  font-size: 13px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
}

/* ── Next runs table ── */
.next-runs {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin-bottom: 24px;
}

.next-runs th,
.next-runs td {
  padding: 8px 12px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.next-runs th {
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.next-runs td {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
}

/* ── Error display ── */
.error-msg {
  display: none;
  padding: 10px 14px;
  font-size: 13px;
  color: var(--red);
  background: rgba(207,34,46,0.1);
  border: 1px solid rgba(207,34,46,0.3);
  border-radius: var(--radius);
  margin-bottom: 12px;
}

/* ── Export overlay ── */
.export-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.5);
  z-index: 10000;
  justify-content: center;
  align-items: flex-start;
  padding-top: 80px;
}

.export-overlay.show {
  display: flex;
}

.export-panel {
  background: var(--bg);
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.2);
  width: 100%;
  max-width: 700px;
  max-height: 80vh;
  overflow-y: auto;
}

.export-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
}

.export-panel-header h2 {
  font-size: 18px;
  font-weight: 600;
}

.export-close {
  background: none;
  border: none;
  font-size: 24px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
}

.export-close:hover {
  background: var(--secondary);
}

.export-tabs {
  display: flex;
  border-bottom: 1px solid var(--border);
  padding: 0 20px;
}

.export-tab {
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 500;
  border: none;
  background: none;
  color: var(--text-secondary);
  cursor: pointer;
  border-bottom: 2px solid transparent;
}

.export-tab:hover {
  color: var(--text);
}

.export-tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.export-body {
  padding: 20px;
}

.export-section {
  display: none;
}

.export-section.active {
  display: block;
}

.export-desc {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.export-output {
  margin-bottom: 16px;
}

.export-output-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
  font-size: 13px;
  font-weight: 600;
}

.export-output pre {
  background: var(--secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
  overflow-x: auto;
  font-size: 12px;
  line-height: 1.5;
}

.export-note {
  font-size: 12px;
  color: var(--text-secondary);
  padding: 10px 14px;
  background: var(--secondary);
  border-radius: var(--radius);
}

/* ── Saved items ── */
.saved-item {
  padding: 8px 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.saved-item:hover {
  background: var(--border);
}

.saved-item-info {
  flex: 1;
}

.saved-item-name {
  font-size: 13px;
  font-weight: 500;
}

.saved-item-expr {
  font-size: 11px;
  color: var(--text-secondary);
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
}

.saved-item-desc {
  font-size: 11px;
  color: var(--text-secondary);
}

.saved-delete {
  background: none;
  border: none;
  color: var(--red);
  cursor: pointer;
  font-size: 14px;
  padding: 4px 8px;
  border-radius: 4px;
}

.saved-delete:hover {
  background: rgba(207,34,46,0.1);
}

/* ── Footer / SEO section ── */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--secondary);
  margin-top: 64px;
  padding: 40px 32px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-secondary);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
}

.footer-section {
  margin-bottom: 28px;
}

.footer-h {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  margin: 0 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.footer-p {
  margin: 0 0 8px;
}

.footer-p code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
  font-size: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 1px 5px;
  border-radius: 3px;
  color: var(--text);
}

.footer-cta {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
}

.footer-cta a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}

.footer-meta {
  border-top: 1px solid var(--border);
  padding-top: 16px;
  margin-top: 16px;
  font-size: 12px;
}

.footer-meta a {
  color: var(--text-secondary);
  text-decoration: none;
}

.footer-meta a:hover {
  color: var(--text);
  text-decoration: underline;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .layout {
    grid-template-columns: 1fr;
  }
  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--border);
    padding: 12px 0;
  }
  .main {
    padding: 16px;
  }
  .presets {
    gap: 6px;
  }
  .preset-btn {
    font-size: 12px;
    padding: 4px 10px;
  }
}