html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    width: 100%;
}

body {
    font-family: Arial, sans-serif;
    background-color: #1a1a1a;
    color: white;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background: lightgreen;
    text-align: center;
    padding: 40px 20px;
    width: 100%;
    box-sizing: border-box;
}

header h1 {
    margin: 0;
    font-size: 2.5em;
    color: black;
}

main {
    flex: 1;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.class-section {
    background-color: rgb(196, 249, 196);
    padding: 60px 20px;
    text-align: center;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    box-sizing: border-box;
}

.class-section h2 {
    font-size: 2em;
    margin-bottom: 40px;
}

.task {
    background-color: #2a2f3a;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    width: 80%;
    max-width: 500px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.task a {
    text-decoration: none;
    color: white;
    font-size: 1.8em;
    font-weight: bold;
    display: block;
    width: 100%;
    text-align: center;
}

footer {
    background-color: darkgreen;
    text-align: center;
    padding: 15px;
    color: white;
    font-size: 1em;
    width: 100%;
    box-sizing: border-box;
}