body {
    font-family: 'Arial', 'Helvetica', 'Malgun Gothic', sans-serif;
    line-height: 1.65;
    margin: 0;
    background-color: #fff;
    color: #222;
}
header {
    text-align: center;
    margin-bottom: 20px;
    padding-top: 40px;
}
header h1 {
    color: #000;
    font-size: 2.4rem;
    margin-bottom: 12px;
}
header p {
    font-size: 1.15em;
    color: #222;
    margin-bottom: 0;
}
main {
    max-width: 750px;
    margin: 0 auto;
    padding: 30px 0 0 0;
}
main h1, main h2 {
    color: #000;
    font-size: 1.7rem;
    margin-top: 28px;
    margin-bottom: 14px;
}
ul {
    list-style-type: disc;
    padding-left: 22px;
    margin-bottom: 22px;
}
li {
    margin-bottom: 10px;
    font-size: 1.07rem;
}
table {
    border-collapse: collapse;
    width: 100%;
    margin: 24px 0;
    background-color: #fff;
    box-shadow: 0 2px 6px rgba(135, 206, 250, 0.3);
    border-radius: 8px;
    overflow: hidden;
}
table th, table td {
    border: 1px solid #ccc;
    padding: 12px 14px;
    text-align: center;
    font-size: 1rem;
    color: #234183;
}
table th {
    background-color: #87ceeb;
    font-weight: 700;
}
hr {
    border: none;
    border-top: 1px solid #bbb;
    margin: 32px 0 18px 0;
}
button.nav {
    margin: 0;
    padding: 11px 18px;
    border: none;
    border-radius: 8px;
    background-color: #87ceeb;
    color: #fff;
    font-size: 1rem;
    font-weight: bold;
    box-shadow: 0 2px 6px rgba(135, 206, 235, 0.16);
    cursor: pointer;
    transition: background-color 0.18s;
    display: inline-block;
}
button.nav:hover {
    background-color: #5dade2;
}
button.nav a {
    color: inherit;
    text-decoration: none;
    font-weight: bold;
}

nav.button-wrapper {
    max-width: 750px;
    margin: 40px auto 60px auto;
    display: flex;
    justify-content: center;
    gap: 10px;
    flex-wrap: wrap;
    text-align: center;
}