*{box-sizing:border-box}body{margin:0;background:#f8f9fc;color:#20283b;font:15px/1.5 system-ui,sans-serif}header,footer{display:flex;align-items:center;justify-content:space-between;padding:22px 5%;border-bottom:1px solid #e2e5ee}header>span,footer{color:#737c90;font-size:13px}.brand{color:#26334b;text-decoration:none;font-weight:750;font-size:18px}main{max-width:1500px;margin:auto;padding:38px 5% 28px}.intro{margin-bottom:28px}.eyebrow{font-size:11px;letter-spacing:2px;font-weight:750;color:#5965d8}h1{font-size:clamp(27px,4vw,38px);line-height:1.2;letter-spacing:-1px;margin:10px 0}.intro>p:last-child{color:#737c90}.toolbar{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}.actions{display:flex;gap:10px;margin-left:auto}button{font:inherit;cursor:pointer;border:1px solid #dce0eb;border-radius:7px;padding:9px 19px;background:white;color:#46516a}button:hover{background:#eef0fa}button:focus-visible,textarea:focus-visible{outline:3px solid #929af4;outline-offset:2px}button.primary{background:#5864dc;color:white;border-color:#5864dc}.primary span{margin-left:16px}.workspace{display:grid;grid-template-columns:1fr 1fr;border:1px solid #dde2ec;border-radius:10px;overflow:hidden;background:white;box-shadow:0 5px 24px #27324b06}.workspace section{min-width:0}#code-panel{border-right:1px solid #dde2ec}.panel-head{height:48px;padding:0 18px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #e5e8f0;font-size:13px;font-weight:650}.panel-head>span:last-child{font-size:11px;color:#8590a4;font-weight:400}textarea{display:block;border:0;resize:vertical;width:100%;height:680px;min-height:240px;padding:22px;background:#fcfcff;color:#35415c;font:13px/1.8 ui-monospace,monospace;tab-size:2}#canvas{height:680px;background:white}iframe{display:block;width:100%;height:100%;border:0}.empty{margin:0;display:flex;flex-direction:column;align-items:center;justify-content:center;height:100%;color:#7e879a;font-size:14px}.empty small{color:#a0a7b7;font-size:12px}.note{color:#7b8498;font-size:12px;margin-top:17px}#error{background:#fff0eb;border:1px solid #efbeac;color:#993c22;border-radius:7px;padding:12px}footer{border-top:1px solid #e2e5ee;border-bottom:0;margin-top:12px}
button.subtle{border-color:transparent;background:transparent;color:#68758c;padding:8px 11px}
button.subtle:hover{background:#eef0fa}

/* Keep both panes visible on phones: code first, preview immediately below. */
@media(max-width:700px){
  header>span{display:none}
  main{padding-top:24px}
  .toolbar{gap:8px}
  .actions{gap:6px;flex-wrap:wrap;justify-content:flex-end;width:100%}
  .actions button{padding:8px 11px}
  .primary span{display:none}
  .workspace{grid-template-columns:minmax(0,1fr)}
  #code-panel{border-right:0;border-bottom:1px solid #dde2ec}
  .panel-head{padding:0 12px}
  textarea{height:clamp(260px,42svh,380px);min-height:260px;resize:vertical}
  #canvas{height:clamp(400px,70svh,650px)}
  footer span{display:none}
}

/* Tabs appear only on narrow screens; desktop retains side-by-side panes. */
.mobile-tabs{display:none}
@media(max-width:700px){
 .mobile-tabs{display:flex;gap:3px;padding:3px;background:#eef0f7;border-radius:8px}
 .mobile-tabs button{border:0;background:transparent;padding:8px 13px;font-size:13px}
 .mobile-tabs button[aria-selected="true"]{background:white;color:#3544ad;box-shadow:0 1px 4px #27324b16}
 .toolbar{align-items:center}
 .workspace[data-mobile-view="code"] #preview-panel{display:none}
 .workspace[data-mobile-view="preview"] #code-panel{display:none}
 #code-panel{border-bottom:0}
 #canvas{height:clamp(400px,70svh,650px)}
}