:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1e222b;
  --fg: #e6e8ec;
  --muted: #8a93a6;
  --accent: #9ae6b4;
  --accent-2: #7cc4ff;
  --border: #272b35;
  --error: #ff6b6b;
  --active-tab-bg: #1a2838;
  --active-tab-border: #3b7bbf;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  height: 100vh;
  overflow: hidden;
}

body {
  display: flex;
  flex-direction: column;
}

header {
  padding: 20px 32px 8px;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

header h1 {
  margin: 0;
  font-size: 22px;
  letter-spacing: 0.02em;
}

header #subtitle {
  grid-column: 1 / 2;
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.lang-switch {
  grid-column: 2 / 3;
  grid-row: 1 / 3;
  display: flex;
  align-items: center;
  gap: 6px;
}

main {
  flex: 1;
  padding: 20px 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  overflow: hidden;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

.options {
  display: flex;
  gap: 24px;
  align-items: center;
  flex-wrap: wrap;
  flex-shrink: 0;
}

.option {
  display: flex;
  align-items: center;
  gap: 8px;
}

.option label {
  color: var(--muted);
  font-size: 13px;
  white-space: nowrap;
}

.checkbox-option {
  gap: 6px;
}

.checkbox-option label {
  cursor: pointer;
}

input[type="text"] {
  padding: 6px 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--fg);
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 14px;
  width: 160px;
}
input[type="text"]:focus {
  outline: none;
  border-color: var(--accent);
}

input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
}

select {
  padding: 6px 10px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--fg);
  font-size: 13px;
}

button {
  padding: 6px 12px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--fg);
  font-size: 13px;
  cursor: pointer;
}
button:hover {
  border-color: var(--accent);
}
#copy-btn, #add-sample-btn {
  background: var(--accent);
  color: #0b1320;
  border: none;
  font-weight: 600;
}
#copy-btn:hover, #add-sample-btn:hover {
  filter: brightness(1.1);
}

.panes {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  min-height: 0;
}

.pane {
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  min-height: 0;
}

.pane-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  background: var(--panel-2);
  border-bottom: 1px solid var(--border);
  color: var(--muted);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  flex-wrap: wrap;
}

.pane-header > span:first-child {
  flex-shrink: 0;
}

.sample-tabs {
  display: flex;
  gap: 4px;
  align-items: center;
  flex: 1;
  flex-wrap: wrap;
}

.sample-tab {
  padding: 4px 10px;
  font-size: 11px;
  text-transform: none;
  letter-spacing: 0;
}
.sample-tab.active {
  background: var(--active-tab-bg);
  border-color: var(--active-tab-border);
  color: var(--accent-2);
}
.sample-tab-remove {
  padding: 4px 6px;
  font-size: 11px;
  color: var(--muted);
}

textarea, #ts-output {
  flex: 1;
  margin: 0;
  padding: 14px 16px;
  background: transparent;
  border: none;
  color: var(--fg);
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
  resize: none;
  overflow: auto;
  min-height: 0;
  white-space: pre;
  tab-size: 2;
}
textarea:focus {
  outline: none;
}

#ts-output {
  color: var(--accent);
}

.error {
  margin: 0;
  padding: 10px 16px;
  background: rgba(255, 107, 107, 0.08);
  border-top: 1px solid rgba(255, 107, 107, 0.3);
  color: var(--error);
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 12px;
}

footer {
  padding: 12px 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 12px;
  text-align: center;
  flex-shrink: 0;
}

@media (max-width: 900px) {
  .panes { grid-template-columns: 1fr; }
  header, main, footer { padding-left: 18px; padding-right: 18px; }
}