/* ==========================
   Cài đặt chung
========================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f7f8;
    color: #333;
    line-height: 1.6;
    padding: 20px;
}

/* ==========================
   Khung chính
========================== */

.container {
    max-width: 800px;
    margin: auto;
    background: #ffffff;
    padding: 30px;
    border-radius: 8px;
    border: 1px solid #ddd;
}

/* ==========================
   Tiêu đề
========================== */

h1 {
    text-align: center;
    color: #2e7d32;
    margin-bottom: 25px;
}

h2 {
    color: #2e7d32;
    margin-bottom: 20px;
}

h3 {
    color: #444;
    margin-bottom: 15px;
}

/* ==========================
   Đoạn văn
========================== */

p {
    margin-bottom: 20px;
}

/* ==========================
   Danh sách đáp án
========================== */

#answers {
    margin-top: 20px;
}

.answer-item {
    display: block;
    margin-bottom: 12px;
    padding: 12px;
    border: 1px solid #cccccc;
    border-radius: 5px;
    cursor: pointer;
    background: #fafafa;
}

.answer-item:hover {
    background: #f0f8f0;
}

.answer-item input {
    margin-right: 10px;
}

/* ==========================
   Nút bấm
========================== */

button {
    background: #2e7d32;
    color: white;
    border: none;
    padding: 12px 24px;
    cursor: pointer;
    border-radius: 5px;
    font-size: 16px;
}

button:hover {
    background: #1b5e20;
}

/* ==========================
   Bảng kết quả
========================== */

table {
    width: 250px;
    border-collapse: collapse;
    margin-top: 15px;
}

table td {
    border: 1px solid #cccccc;
    padding: 10px;
}

table tr:first-child td,
table tr:nth-child(2) td,
table tr:nth-child(3) td,
table tr:nth-child(4) td,
table tr:nth-child(5) td {
    text-align: center;
}

/* ==========================
   Đường kẻ
========================== */

hr {
    margin: 25px 0;
}

/* ==========================
   Responsive
========================== */

@media (max-width: 768px) {

    .container {
        padding: 20px;
    }

    h1 {
        font-size: 24px;
    }

    button {
        width: 100%;
    }

    table {
        width: 100%;
    }

}