:root{color-scheme:light}*{box-sizing:border-box}body{margin:0;min-height:100vh;font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:radial-gradient(circle at top left,#1f6bff,#0d1b4a 45%,#6f0018);color:#eef3ff}.app-shell{max-width:980px;margin:28px auto;padding:24px;border-radius:24px;background:linear-gradient(145deg,#091a4ee0,#7c0a27d1);border:1px solid rgba(255,255,255,.18);box-shadow:0 16px 40px #00000059;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px)}.app-title{margin:0 0 8px;font-size:clamp(1.8rem,3.5vw,2.6rem)}.app-subtitle{margin:0 0 22px;color:#c9d8ff}.ui-grid{display:grid;gap:16px;grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}.card{padding:16px;border-radius:16px;border:1px solid rgba(255,255,255,.18);background:linear-gradient(160deg,#1638917a,#ba124a57)}.card h3{margin-top:0}.feedback-card{margin-top:16px;background:linear-gradient(160deg,#1962ff73,#ff336652)}.canvas-pro{width:100%;max-width:420px;border:2px solid rgba(129,181,255,.85);border-radius:10px;background:#f7faff;cursor:crosshair}.file-input,.tutor-input,.tutor-btn{border-radius:10px;border:1px solid transparent;padding:10px 12px;font:inherit}.file-input,.tutor-input{width:100%;background:#e9f2fff2;color:#10224e}.tutor-messages{margin:0 0 10px;padding:10px;max-height:220px;overflow-y:auto;border-radius:12px;border:1px solid rgba(146,186,255,.45);background:#08102d73}.msg{margin-bottom:8px;line-height:1.45}.msg-user strong{color:#8bc2ff}.msg-ai strong{color:#ff7ca1}.tutor-controls{display:flex;gap:8px}.tutor-btn{min-width:88px;color:#fff;border-color:#ffffff59;background:linear-gradient(135deg,#2f7dff,#e91e63);cursor:pointer}.tutor-btn:hover{filter:brightness(1.07)}