body{margin:0;padding:0;font-family:Segoe UI,Arial,sans-serif;background-color:#f5f6fa;color:#222}header{background-color:#2b6cb0;color:#fff;padding:12px 20px;display:flex;justify-content:space-between;align-items:center;box-shadow:0 2px 4px #0000001a}h1{margin:0;font-size:20px;letter-spacing:.5px}nav button{margin-left:10px;border:none;background-color:#fff;color:#2b6cb0;font-weight:500;border-radius:5px;padding:6px 12px;cursor:pointer;transition:all .2s ease}nav button:hover{background-color:#edf2f7}nav button.active{background-color:#2b6cb0;color:#fff}main{padding:20px}.card{background-color:#fff;border-radius:6px;box-shadow:0 2px 6px #0000000d;padding:16px;margin-bottom:16px}.user-list{display:flex;flex-direction:column;gap:8px}.user-item{background:#fff;padding:10px 14px;border-radius:5px;border:1px solid #e2e8f0;cursor:pointer}.user-item:hover{background:#f0f4ff}.message{padding:8px 12px;border-radius:6px;margin-bottom:8px;max-width:80%}.message.user{background-color:#e2e8f0;text-align:left}.message.tutor{background-color:#bee3f8;text-align:right;margin-left:auto}img{max-width:180px;border-radius:6px}