body {
    font-family: Arial, sans-serif;
    background-color: #f4f7f6;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}
.container { width: 100%; max-width: 400px; padding: 20px; }
.card {
    background: white;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    text-align: center;
}
textarea {
    width: 100%; height: 100px; padding: 10px;
    margin: 15px 0; border: 1px solid #ddd; border-radius: 8px;
    resize: none; box-sizing: border-box;
}
button {
    width: 100%; background: #007bff; color: white;
    border: none; padding: 12px; border-radius: 8px;
    cursor: pointer; font-size: 16px;
}
.hidden { display: none; }
.positive { background: #d4edda; color: #155724; border: 1px solid #c3e6cb; padding: 10px; border-radius: 8px; margin-top: 20px;}
.negative { background: #f8d7da; color: #721c24; border: 1px solid #f5c6cb; padding: 10px; border-radius: 8px; margin-top: 20px;}
.spinner {
    border: 4px solid #f3f3f3; border-top: 4px solid #007bff;
    border-radius: 50%; width: 30px; height: 30px;
    animation: spin 1s linear infinite; margin: 20px auto;
}
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }