*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }

:root {
  color-scheme: dark;
  --bg: #0b0d10;
  --panel: #1c2128;
  --panel-2: #262d36;
  --text: #f5f7fa;
  --muted: #b4bcc4;
  --muted-2: #828a93;
  --accent: #ffb000;
  --accent-soft: rgba(255, 176, 0, 0.16);
  --border: #3a434d;
  --border-strong: #525c66;
  --danger: #ff7575;
  --success: #75e0ad;
  --radius: 12px;
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.25);
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, system-ui, sans-serif;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
  position: sticky;
  top: 0;
  z-index: 10;
}
.brand { font-weight: 600; letter-spacing: 0.2px; }
.env-badge {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--muted);
  padding: 4px 10px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
}

.layout {
  display: grid;
  grid-template-columns: minmax(340px, 400px) 1fr;
  gap: 16px;
  padding: 16px;
  height: calc(100vh - 53px);
}
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  overflow: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* INPUT PANEL */
.input-panel h1 {
  font-size: 18px;
  margin: 0 0 4px;
  font-weight: 600;
}

.field { display: flex; flex-direction: column; gap: 6px; }
.field-label {
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.4px;
  font-weight: 600;
}

select, input[type="url"], input[type="text"], textarea {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 9px 11px;
  color: var(--text);
  font: inherit;
  width: 100%;
  resize: vertical;
}
select:focus, input:focus, textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  border-color: var(--accent);
}
textarea { line-height: 1.5; min-height: 80px; }

.segmented {
  display: flex;
  gap: 6px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 4px;
}
.seg-btn {
  flex: 1;
  background: transparent;
  color: var(--muted);
  border: 0;
  border-radius: 6px;
  padding: 7px 8px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1px;
  transition: background 120ms ease;
}
.seg-btn:hover { color: var(--text); }
.seg-btn.is-active {
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
}
.seg-sub {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.4px;
  color: var(--muted-2);
  font-weight: 500;
}
.seg-btn.is-active .seg-sub { color: var(--accent); opacity: 0.7; }

button.primary {
  background: var(--accent);
  color: #1a1100;
  border: 0;
  border-radius: 8px;
  padding: 12px 14px;
  font: inherit;
  font-weight: 700;
  font-size: 14px;
  cursor: pointer;
  margin-top: 4px;
  transition: filter 120ms ease, transform 60ms ease;
}
button.primary:hover { filter: brightness(1.08); }
button.primary:active { transform: scale(0.99); }
button.primary:disabled { opacity: 0.5; cursor: not-allowed; }

button.ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border-strong);
  border-radius: 7px;
  padding: 6px 11px;
  font: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: color 120ms ease, border-color 120ms ease;
}
button.ghost:hover { color: var(--text); border-color: var(--accent); }

.hint { font-size: 12px; color: var(--muted); margin: 0; }

.history { font-size: 12px; color: var(--muted); margin-top: auto; }
.history summary { cursor: pointer; padding: 4px 0; }
.history ul {
  list-style: none;
  padding: 0;
  margin: 8px 0 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.history li {
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  color: var(--text);
}
.history li:hover { border-color: var(--accent); }

/* OUTPUT PANEL */
.output-panel { padding: 0; }
.output-empty, .output-loading, .output-error, .output-result {
  padding: 20px 24px;
}
.output-empty, .output-loading, .output-error {
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
}
.output-empty h2, .output-loading h2, .output-error h2 {
  margin: 8px 0 4px;
  font-size: 16px;
  font-weight: 600;
}
.output-empty p, .output-loading p { color: var(--muted); margin: 0; }
.output-error pre {
  color: var(--danger);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  max-width: 600px;
  white-space: pre-wrap;
  word-break: break-word;
  text-align: left;
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border-strong);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
  margin-bottom: 8px;
}
@keyframes spin { to { transform: rotate(360deg); } }

.output-result { display: flex; flex-direction: column; gap: 14px; height: 100%; overflow: hidden; }
.result-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}
.result-head h2 { margin: 0; font-size: 18px; font-weight: 600; }
.result-head .muted { color: var(--muted); margin: 4px 0 0; font-size: 12px; }
.result-actions { display: flex; gap: 8px; flex-shrink: 0; }

.tabs {
  display: flex;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
}
.tab {
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  padding: 10px 14px;
  color: var(--muted);
  cursor: pointer;
  font: inherit;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
  white-space: nowrap;
}
.tab-letter { font-size: 16px; font-weight: 700; line-height: 1.1; }
.tab-name { font-size: 11px; text-transform: uppercase; letter-spacing: 0.4px; color: var(--muted-2); }
.tab.is-active { color: var(--accent); border-bottom-color: var(--accent); }
.tab.is-active .tab-name { color: var(--accent); opacity: 0.85; }

.variation-actions {
  display: flex;
  gap: 8px;
  align-items: center;
  padding-bottom: 4px;
}
.copy-flash {
  font-size: 12px;
  color: var(--success);
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(107, 214, 163, 0.1);
}

.variation {
  flex: 1;
  overflow: auto;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 22px;
}
.variation h1, .variation h2, .variation h3 {
  color: var(--text);
  margin: 22px 0 12px;
  font-weight: 700;
}
.variation h2 {
  font-size: 19px;
  color: var(--accent);
  border-bottom: 2px solid var(--accent);
  padding-bottom: 10px;
  margin-top: 28px;
}
.variation h3 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text);
  margin-top: 22px;
  padding: 6px 10px;
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
}
.variation > :first-child { margin-top: 0; }
.variation p { margin: 12px 0; color: var(--text); }
.variation ul, .variation ol { padding-left: 22px; margin: 12px 0; }
.variation li { margin: 6px 0; color: var(--text); }
.variation strong { color: var(--text); font-weight: 700; }
.variation hr { border: 0; border-top: 1px solid var(--border-strong); margin: 22px 0; }
.variation code {
  background: var(--bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
}
.variation pre {
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 12px;
  border-radius: 6px;
  overflow-x: auto;
}

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; height: auto; }
  .panel { max-height: none; }
}