* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
    background: #f1f3f5;
}

.box {
    width: 600px;
    max-width: 90%;
    margin: 120px auto;
    background: #ffffff;
    padding: 35px 40px;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    text-align: center;
}

.box h3 {
    margin-bottom: 25px;
    font-size: 22px;
    font-weight: 600;
    color: #000;
}

input[type="text"],
button {
    width: 100%;
    height: 48px;             
    font-size: 15px;
    border-radius: 6px;
}

input[type="text"] {
    padding: 0 12px;
    border: 1px solid #ccc;
    outline: none;
    margin-bottom: 18px;
}

input[type="text"]:focus {
    border-color: #3b7ddd;
}

button {
    padding: 0;
    background: #3b7ddd;   
    color: #fff;
    border: none;
    cursor: pointer;
}

button:hover {
    background: #2f68c5;
}

.result-box {
    margin-top: 25px;
    text-align: left;
    background: #f8f9fa;
    padding: 18px;
    border-radius: 6px;
    font-size: 14px;
}

.result-box ul {
    margin: 8px 0 0 18px;
}

.error {
    margin-top: 15px;
    color: red;
    font-size: 14px;
}