:root {
  --bg: #111118;
  --bg-card: #1a1a24;
  --bg-input: #0d0d14;
  --text: #e0e0e8;
  --text-secondary: #9898a8;
  --text-muted: #5c5c70;
  --primary: #6366f1;
  --primary-light: #818cf8;
  --border: rgba(99,102,241,0.1);
  --border-strong: rgba(99,102,241,0.25);
  --shadow: 0 4px 14px rgba(0,0,0,0.4);
  --radius: 10px;
  --font: 'Inter',-apple-system,sans-serif;
  --mono: 'JetBrains Mono',monospace;
  --transition: 0.2s ease;
  --glass: rgba(26,26,36,0.92);
  --error: #f43f5e;
  --tag: #818cf8;
  --attr: #34d399;
  --string: #fbbf24;
  --comment: #5c5c70;
}

@media(prefers-color-scheme:light){
  :root{--bg:#f8f9fb;--bg-card:#fff;--bg-input:#f1f3f5;--text:#1e1e2e;--text-secondary:#5c5c70;--text-muted:#9898a8;--border:rgba(99,102,241,0.12);--shadow:0 4px 14px rgba(0,0,0,0.06);--glass:rgba(255,255,255,0.92)}
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh;overflow:hidden}

.header{background:var(--glass);backdrop-filter:blur(12px);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:50}
.header-inner{padding:8px 16px;display:flex;align-items:center;justify-content:space-between;gap:8px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:8px}
.logo h1{font-size:1rem;font-weight:700;color:var(--primary-light)}
.header-actions{display:flex;align-items:center;gap:4px;flex-wrap:wrap}
.separator{width:1px;height:18px;background:var(--border);margin:0 4px}

.btn{padding:5px 10px;border:1px solid var(--border);border-radius:8px;background:transparent;color:var(--text-secondary);font-family:var(--font);font-size:0.75rem;font-weight:500;cursor:pointer;transition:all var(--transition);white-space:nowrap}
.btn:hover{border-color:var(--primary);color:var(--primary)}
.btn.active{background:rgba(99,102,241,0.1);border-color:var(--primary);color:var(--primary-light)}

.select{padding:5px 8px;border:1px solid var(--border);border-radius:8px;background:transparent;color:var(--text-secondary);font-family:var(--font);font-size:0.75rem;cursor:pointer;appearance:auto}
.select:focus{outline:none;border-color:var(--primary)}

.main{height:calc(100vh - 48px);display:flex;flex-direction:column}
.editor-layout{flex:1;display:flex;gap:0;overflow:hidden}

.panel{flex:1;display:flex;flex-direction:column;min-width:0}
.panel:first-child{border-right:1px solid var(--border)}
.panel-header{display:flex;align-items:center;justify-content:space-between;padding:8px 14px;border-bottom:1px solid var(--border)}
.panel-header h2{font-size:0.78rem;font-weight:600;color:var(--primary-light)}
.badge{font-size:0.65rem;padding:2px 6px;border-radius:4px;background:rgba(99,102,241,0.08);color:var(--text-muted)}

.code-area{flex:1;padding:14px;background:var(--bg-input);color:var(--text);font-family:var(--mono);font-size:0.8rem;line-height:1.6;border:none;resize:none;overflow:auto;tab-size:2;white-space:pre}
.code-area:focus{outline:none}
textarea.code-area{display:block;width:100%;height:100%;min-height:0}
.output-area{cursor:text;user-select:text}

/* Syntax Highlighting */
.xml-tag{color:var(--tag)}
.xml-attr{color:var(--attr)}
.xml-string{color:var(--string)}
.xml-comment{color:var(--comment);font-style:italic}
.xml-text{color:var(--text-secondary)}

/* Tree View */
.tree-wrap{flex:1;overflow:auto;padding:10px 14px;background:var(--bg-input)}
.tree{font-family:var(--mono);font-size:0.78rem}
.tree-node{padding-left:18px;position:relative}
.tree-node::before{content:'';position:absolute;left:4px;top:0;bottom:0;width:1px;background:var(--border)}
.tree-toggle{cursor:pointer;color:var(--primary);font-weight:600;padding:2px 0;display:flex;align-items:center;gap:4px}
.tree-toggle .arrow{font-size:0.6rem;transition:transform .2s}
.tree-toggle .arrow.open{transform:rotate(90deg)}
.tree-leaf{color:var(--text-secondary);padding:2px 0 2px 14px}
.tree-tag{color:var(--tag)}
.tree-attr{color:var(--attr);font-size:0.7rem}

.error-bar{padding:8px 14px;background:rgba(244,63,94,0.08);border-top:1px solid rgba(244,63,94,0.2);color:var(--error);font-size:0.78rem}

@media(max-width:640px){
  .editor-layout{flex-direction:column}
  .panel:first-child{border-right:none;border-bottom:1px solid var(--border)}
  .panel{min-height:35vh}
}