body {
    font-family: 'Roboto', sans-serif;
    background-color: #F8F9FA;
    margin: 0;
    padding: 0;
    min-height: 100vh;
}
.navbar {
    background-color: #007BFF;
    padding: 10px 0;
}
.navbar ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
}
.navbar ul li {
    margin: 0 15px;
}
.navbar ul li a {
    color: #FFFFFF;
    text-decoration: none;
    font-weight: 500;
}
.navbar ul li a:hover {
    color: #DDD;
}
.container {
    max-width: 1400px;
    margin: 20px auto;
    padding: 40px;
    background-color: #FFFFFF;
    border-radius: 15px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}
.form-group {
    margin-bottom: 25px;
}
label {
    display: block;
    font-weight: 500;
    color: #333;
    margin-bottom: 8px;
}
input[type="text"], input[type="password"], input[type="date"], select, input[type="number"] {
    width: 100%;
    padding: 12px;
    border: 1px solid #CED4DA;
    border-radius: 8px;
    font-size: 16px;
    box-sizing: border-box;
    transition: border-color 0.3s;
}
input[type="text"]:focus, input[type="password"]:focus, input[type="date"]:focus, select:focus, input[type="number"]:focus {
    border-color: #007BFF;
    outline: none;
}
.btn_1 {
    width: 100%;
    padding: 14px;
    background: linear-gradient(90deg, #007BFF, #0056B3);
    border: none;
    border-radius: 8px;
    color: #FFFFFF;
    font-weight: 500;
    font-size: 18px;
    cursor: pointer;
    transition: opacity 0.3s;
}
.btn_1:hover {
    opacity: 0.9;
}
.error {
    color: #DC3545;
    font-weight: 500;
    text-align: center;
    margin-top: 10px;
}
table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: 10px;
    overflow: hidden;
    background: linear-gradient(145deg, #F8F9FA, #FFFFFF);
    margin-top: 20px;
}
th, td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #DEE2E6;
}
th {
    background-color: #007BFF;
    color: #FFFFFF;
    font-weight: 500;
}
td {
    color: #333;
}
tr:last-child td {
    border-bottom: none;
}
tr:hover {
    background-color: #F1F3F5;
}
h1, h2, h3 {
    color: #007BFF;
    text-align: center;
}
h1 { font-size: 24px; }
h2 { font-size: 22px; }
h3 { font-size: 20px; }
@media (max-width: 480px) {
    .container {
        padding: 15px;
        margin: 10px;
        width: 100%;
        max-width: 100%;
    }
    input[type="text"], input[type="password"], input[type="date"], select, input[type="number"], .btn_1 {
        font-size: 14px;
        padding: 10px;
    }
    .btn_1 {
        font-size: 16px;
    }
    h1 { font-size: 20px; }
    h2 { font-size: 18px; }
    h3 { font-size: 16px; }
    table, thead, tbody, th, td, tr {
        display: block;
    }
    thead tr {
        position: absolute;
        top: -9999px;
        left: -9999px;
    }
    tr {
        margin-bottom: 15px;
        border: 1px solid #DEE2E6;
        border-radius: 8px;
    }
    td {
        border: none;
        position: relative;
        padding-left: 50%;
        text-align: right;
        font-size: 14px;
    }
    td:before {
        content: attr(data-label);
        position: absolute;
        left: 10px;
        width: 45%;
        padding-right: 10px;
        font-weight: 500;
        text-align: left;
        color: #555;
    }
    td:nth-of-type(1):before { content: "Số thứ tự"; }
    td:nth-of-type(2):before { content: "Tên miền"; }
    td:nth-of-type(3):before { content: "Thời gian truy vấn"; }
    td:nth-of-type(4):before { content: "Ngày tạo"; }
    td:nth-of-type(5):before { content: "Ngày cập nhật"; }
    td:nth-of-type(6):before { content: "Ngày hết hạn"; }
    td:nth-of-type(7):before { content: "Nhà đăng ký"; }
    td:nth-of-type(8):before { content: "Tên đầy đủ"; }
    td:nth-of-type(9):before { content: "Tên công ty"; }
    .navbar ul {
        flex-direction: column;
        align-items: center;
    }
    .navbar ul li {
        margin: 10px 0;
    }
}