body {
    font-family: sans-serif;
    margin: 20px;
    background-color: #f0f0f0;
    color: #333;
    transition: background-color 0.3s, color 0.3s;
}

body.night-mode {
    background-color: #333;
    color: #f0f0f0;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: background-color 0.3s;
}

body.night-mode .container {
    background-color: #424242;
    box-shadow: 0 2px 4px rgba(0,0,0,0.5);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

h1 {
    margin: 0;
}

button, input[type="text"] {
    padding: 10px;
    border-radius: 5px;
    border: 1px solid #ccc;
    font-size: 16px;
}

button {
    cursor: pointer;
    background-color: #007bff;
    color: white;
    border-color: #007bff;
}

button:disabled {
    background-color: #ccc;
    border-color: #ccc;
    cursor: not-allowed;
}

body.night-mode button {
    background-color: #0056b3;
    border-color: #0056b3;
}

body.night-mode button:disabled {
    background-color: #555;
    border-color: #555;
}

#theme-toggle {
    background-color: #6c757d;
    border-color: #6c757d;
}

body.night-mode #theme-toggle {
    background-color: #f8f9fa;
    color: #333;
    border-color: #f8f9fa;
}

input[type="text"] {
    width: calc(100% - 22px);
    margin-bottom: 10px;
}

body.night-mode input[type="text"] {
    background-color: #555;
    color: #f0f0f0;
    border-color: #666;
}

.past-test {
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    margin-top: 10px;
}

body.night-mode .past-test {
    border-color: #555;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th, td {
    padding: 8px;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

body.night-mode th, body.night-mode td {
    border-bottom: 1px solid #555;
}

th {
    background-color: #f2f2f2;
}

body.night-mode th {
    background-color: #505050;
}

.crossed-out {
    text-decoration: line-through;
}