:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --bg: #0f172a;
    --bg-card: #1e293b;
    --bg-editor: #282a36;
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --border: #334155;
    --success: #22c55e;
    --error: #ef4444;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; background: var(--bg); color: var(--text); min-height: 100vh; line-height: 1.5; }
.container { max-width: 1400px; margin: 0 auto; padding: 12px; }
.back-link { display: inline-block; color: var(--text-muted); text-decoration: none; margin-bottom: 8px; font-size: 0.85rem; transition: color 0.2s; }
.back-link:hover { color: var(--primary); }
header { text-align: center; padding: 10px; margin-bottom: 12px; border-bottom: 1px solid var(--border); }
header h1 { font-size: 1.4rem; margin-bottom: 2px; background: linear-gradient(135deg, #6366f1, #a855f7); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
header p { color: var(--text-muted); font-size: 0.85rem; }

.toolbar {
    display: flex; justify-content: space-between; align-items: center;
    background: var(--bg-card); padding: 8px 14px; border-radius: 6px 6px 0 0;
    border: 1px solid var(--border); border-bottom: none; flex-wrap: wrap; gap: 8px;
}
.tool-group { display: flex; align-items: center; gap: 6px; }
.tool-group.actions { margin-left: auto; flex-wrap: wrap; }
select { background: var(--bg); color: var(--text); border: 1px solid var(--border); padding: 6px 10px; border-radius: 4px; outline: none; cursor: pointer; font-size: 0.85rem; }
button { cursor: pointer; border: none; padding: 6px 12px; border-radius: 4px; font-weight: 500; display: flex; align-items: center; gap: 6px; transition: all 0.2s; font-size: 0.8rem; }
.primary-btn { background: var(--primary); color: white; }
.primary-btn:hover { background: var(--primary-hover); }
.secondary-btn { background: var(--border); color: var(--text); }
.secondary-btn:hover { background: #475569; }
.icon-btn { background: transparent; color: var(--text-muted); padding: 6px; font-size: 1rem; }
.icon-btn:hover { color: var(--text); background: rgba(255,255,255,0.05); }
.text-btn { background: transparent; color: var(--primary); padding: 2px 6px; font-size: 0.7rem; cursor: pointer; border: none; }
.text-btn:hover { text-decoration: underline; }

.editor-container {
    display: flex; height: calc(100vh - 240px); min-height: 400px; border: 1px solid var(--border);
    background: var(--bg-card); overflow: hidden;
}
.editor-container.stack { flex-direction: column; height: calc(100vh - 200px); min-height: 500px; }
.editor-pane { flex: 1; display: flex; flex-direction: column; min-width: 0; min-height: 0; border-right: 1px solid var(--border); }
.editor-container.stack .editor-pane { border-right: none; border-bottom: 1px solid var(--border); }
.editor-pane:last-child { border-right: none; border-bottom: none; }
.pane-header {
    padding: 6px 12px; background: #21222c; font-size: 0.8rem; color: var(--text-muted);
    font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em;
    display: flex; justify-content: space-between; align-items: center;
}
.CodeMirror { height: 100% !important; font-family: 'Fira Code', 'Consolas', monospace; font-size: 13px; flex: 1; }
#input-editor, #output-editor { flex: 1; overflow: hidden; position: relative; min-height: 0; }

.dropdown { position: relative; display: inline-block; }
.dropdown-content {
    display: none; position: absolute; background-color: var(--bg-card);
    min-width: 150px; box-shadow: 0 8px 16px rgba(0,0,0,0.5); z-index: 100;
    border: 1px solid var(--border); border-radius: 4px; top: 100%; right: 0;
}
.dropdown-content button { color: var(--text); padding: 8px 12px; display: block; width: 100%; text-align: left; background: transparent; border-radius: 0; font-size: 0.8rem; border: none; cursor: pointer; }
.dropdown-content button:hover { background-color: var(--primary); }
.dropdown-content hr { border: 0; border-top: 1px solid var(--border); margin: 3px 0; }
.dropdown:hover .dropdown-content { display: block; }

.status { font-size: 0.75rem; text-transform: none; }
.status.success { color: var(--success); }
.status.error { color: var(--error); }

.options-panel { margin-top: 12px; padding: 12px; background: var(--bg-card); border-radius: 6px; border: 1px solid var(--border); }
.options-flex { display: flex; gap: 30px; flex-wrap: wrap; }
.option-section { flex: 1; min-width: 200px; }
.option-section h3 { margin-bottom: 8px; font-size: 0.95rem; color: var(--primary); }
.option-group { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; font-size: 0.85rem; }
.option-group label { display: flex; align-items: center; gap: 6px; cursor: pointer; }
input[type="number"] { background: var(--bg); border: 1px solid var(--border); color: var(--text); padding: 3px 6px; border-radius: 4px; width: 50px; }
input[type="checkbox"] { accent-color: var(--primary); }

/* Preview panel for Markdown/HTML */
.preview-panel {
    margin-top: 12px; border: 1px solid var(--border); border-radius: 6px;
    background: var(--bg-card); overflow: hidden;
}
.preview-content {
    padding: 16px; max-height: 60vh; overflow-y: auto;
    background: #fff; color: #1a1a1a; font-size: 0.9rem; line-height: 1.6;
}
.preview-content h1, .preview-content h2, .preview-content h3 { margin: 12px 0 6px; }
.preview-content p { margin: 6px 0; }
.preview-content code { background: #f0f0f0; padding: 2px 4px; border-radius: 3px; font-size: 0.85em; }
.preview-content pre { background: #f5f5f5; padding: 10px; border-radius: 4px; overflow-x: auto; }
.preview-content pre code { background: none; padding: 0; }
.preview-content table { border-collapse: collapse; width: 100%; margin: 8px 0; }
.preview-content th, .preview-content td { border: 1px solid #ddd; padding: 6px 10px; text-align: left; }
.preview-content th { background: #f5f5f5; }
.preview-content img { max-width: 100%; }
.preview-content ul, .preview-content ol { padding-left: 24px; }
.preview-content blockquote { border-left: 3px solid #6366f1; padding-left: 12px; color: #555; margin: 8px 0; }

/* Language-specific action buttons */
#lang-actions { display: flex; gap: 4px; }
#lang-actions button { padding: 5px 10px; font-size: 0.78rem; }

@media (max-width: 768px) {
    .editor-container { flex-direction: column; height: 700px; }
    .editor-pane { border-right: none; border-bottom: 1px solid var(--border); height: 50%; }
}

/* Collapsible JSON/YAML tree viewer */
.tree-viewer { font-family: 'Fira Code', 'Consolas', monospace; font-size: 0.82rem; line-height: 1.6; }
.tree-node { padding-left: 18px; position: relative; }
.tree-key { color: #0550ae; font-weight: 600; }
.tree-string { color: #0a3069; }
.tree-number { color: #0550ae; }
.tree-boolean { color: #cf222e; }
.tree-null { color: #6e7781; font-style: italic; }
.tree-toggle {
    cursor: pointer; user-select: none; display: inline-flex; align-items: center; gap: 4px;
    padding: 1px 0; border: none; background: none; font: inherit; color: inherit;
}
.tree-toggle:hover { background: rgba(99,102,241,0.1); border-radius: 3px; }
.tree-toggle::before {
    content: '▶'; display: inline-block; font-size: 0.6em; transition: transform 0.15s;
    color: var(--text-muted);
}
.tree-toggle.open::before { transform: rotate(90deg); }
.tree-bracket { color: #6e7781; }
.tree-comma { color: #6e7781; }
.tree-count { color: #8b949e; font-size: 0.75rem; font-style: italic; margin-left: 4px; }
.tree-children { overflow: hidden; }
.tree-children.collapsed { display: none; }