/* Simple responsive light theme */
*{box-sizing:border-box}
body{font-family:Inter,Arial,Helvetica,sans-serif;margin:0;background:#f4f7fb;color:#222}
.topbar{display:flex;justify-content:space-between;align-items:center;padding:12px 18px;background:#fff;border-bottom:1px solid #e6e9ee;position:sticky;top:0;z-index:10}
.brand{font-weight:700}
.user a{color:#0073e6;text-decoration:none}
.container{display:flex;max-width:1100px;margin:20px auto;padding:0 12px}
.sidebar{width:220px;padding:12px;background:transparent}
.sidebar ul{list-style:none;padding:0;margin:0}
.sidebar a{display:block;padding:10px 8px;color:#333;text-decoration:none;border-radius:6px}
.sidebar a:hover{background:#eef4ff}
.content{flex:1;padding:0 12px}
.cards{display:flex;gap:12px;flex-wrap:wrap;margin-bottom:16px}
.card{background:#fff;padding:14px;border-radius:8px;flex:1;min-width:180px;box-shadow:0 1px 4px rgba(16,24,40,0.06)}
.course-list{display:flex;flex-direction:column;gap:10px}
.course{background:#fff;padding:12px;border-radius:8px;box-shadow:0 1px 4px rgba(16,24,40,0.04)}
.progress-bar{background:#eef2f7;height:10px;border-radius:6px;overflow:hidden;margin:8px 0}
.progress{height:10px;background:#28a745;width:0%}
.auth-wrap{display:flex;min-height:80vh;align-items:center;justify-content:center;padding:20px}
.auth-card{background:#fff;padding:20px;border-radius:8px;min-width:280px;max-width:420px;box-shadow:0 6px 18px rgba(18,38,63,0.06)}
.auth-card h2{margin-top:0}
.auth-card input[type=text], .auth-card input[type=password], .auth-card input[type=email], .auth-card input[type=number]{width:100%;padding:10px;margin:8px 0;border:1px solid #dfe7ef;border-radius:6px}
.auth-card button{width:100%;padding:10px;background:#0073e6;color:#fff;border:none;border-radius:6px;cursor:pointer}
.error{background:#fff0f0;color:#a60000;padding:8px;border-radius:6px}
@media(max-width:800px){
  .container{flex-direction:column;padding:8px}
  .sidebar{width:100%;order:2;padding:8px 0}
  .content{order:1}
  .cards{flex-direction:column}
}