:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #1c2128;
    --bg-editor: #0d1117;
    --border: #30363d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #484f58;
    --accent: #58a6ff;
    --accent-glow: rgba(88, 166, 255, 0.15);
    --green: #3fb950;
    --yellow: #d29922;
    --red: #f85149;
    --purple: #bc8cff;
    --orange: #f0883e;
    --cyan: #53d8fb;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Menlo', 'Consolas', monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif;
}

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

html, body {
    height: 100%;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    overflow: hidden;
}

/* ---- Header ---- */
header {
    height: 52px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    flex-shrink: 0;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo { height: 32px; width: 32px; object-fit: contain; border-radius: 6px; }

header h1 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.badge {
    font-size: 0.65rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--purple);
    background: rgba(188, 140, 255, 0.1);
    border: 1px solid rgba(188, 140, 255, 0.25);
    padding: 2px 8px;
    border-radius: 10px;
}

.header-right { display: flex; align-items: center; gap: 12px; }

.gh-link {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    transition: color 0.15s;
}
.gh-link:hover { color: var(--text-primary); }

/* ---- Main layout ---- */
main {
    display: flex;
    height: calc(100vh - 52px - 32px);
    overflow: hidden;
}

/* ---- Editor panel ---- */
.editor-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border);
    min-width: 0;
}

.panel-header {
    height: 42px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 12px;
    flex-shrink: 0;
}

.panel-title {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

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

#example-select {
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 4px 10px;
    font-family: var(--font-sans);
    font-size: 0.82rem;
    border-radius: 6px;
    cursor: pointer;
    outline: none;
}
#example-select:focus { border-color: var(--accent); }

.panel-actions { display: flex; gap: 6px; }

.btn-primary {
    display: flex;
    align-items: center;
    gap: 5px;
    background: var(--green);
    color: #fff;
    border: none;
    padding: 5px 14px;
    font-family: var(--font-sans);
    font-size: 0.82rem;
    font-weight: 600;
    border-radius: 6px;
    cursor: pointer;
    transition: opacity 0.15s;
}
.btn-primary:hover { opacity: 0.9; }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border);
    padding: 4px 10px;
    font-family: var(--font-sans);
    font-size: 0.78rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.15s;
}
.btn-ghost:hover { color: var(--text-primary); border-color: var(--text-muted); }

/* ---- Code editor (overlay approach) ---- */
.editor-wrap {
    flex: 1;
    position: relative;
    overflow: hidden;
}

#editor, #highlight {
    font-family: var(--font-mono);
    font-size: 14px;
    line-height: 1.6;
    padding: 16px 20px;
    white-space: pre;
    tab-size: 4;
    word-wrap: normal;
    overflow-wrap: normal;
}

#highlight {
    position: absolute;
    inset: 0;
    margin: 0;
    overflow: auto;
    pointer-events: none;
    background: var(--bg-editor);
    color: var(--text-primary);
}
#highlight code {
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
}

#editor {
    position: relative;
    z-index: 1;
    width: 100%;
    height: 100%;
    background: transparent;
    color: transparent;
    caret-color: var(--accent);
    border: none;
    outline: none;
    resize: none;
    overflow-y: auto;
}

/* ---- Syntax highlighting tokens ---- */
.hl-kw { color: var(--purple); font-weight: 600; }
.hl-type { color: var(--cyan); }
.hl-str { color: var(--green); }
.hl-num { color: var(--orange); }
.hl-comment { color: var(--text-muted); font-style: italic; }
.hl-builtin { color: var(--accent); }
.hl-bool { color: var(--orange); font-weight: 600; }
.hl-op { color: var(--text-secondary); }
.hl-punct { color: var(--text-muted); }

/* ---- Output panel ---- */
.output-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

#console {
    flex: 1;
    background: var(--bg-editor);
    font-family: var(--font-mono);
    font-size: 13px;
    line-height: 1.7;
    padding: 12px 16px;
    overflow-y: auto;
}

.log { padding: 1px 0; }
.log .ts { color: var(--text-muted); margin-right: 8px; font-size: 0.85em; }
.log.info { color: var(--text-primary); }
.log.system { color: var(--purple); }
.log.warn { color: var(--yellow); }
.log.error { color: var(--red); }
.log.success { color: var(--green); }


/* ---- Footer ---- */
footer {
    height: 32px;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-size: 0.75rem;
    color: var(--text-muted);
    flex-shrink: 0;
}
footer a { color: var(--text-secondary); text-decoration: none; }
footer a:hover { color: var(--text-primary); }
.sep { color: var(--border); }

/* ---- Responsive ---- */
@media (max-width: 768px) {
    main { flex-direction: column; }
    .editor-panel { border-right: none; border-bottom: 1px solid var(--border); flex: none; height: 45%; }
    .output-panel { flex: 1; }
}

/* ---- Scrollbar ---- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }