body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    transition: background-color 0.3s, color 0.3s;
}

body.light-mode {
    background-color: #f4f4f4;
    color: #000;
}

body.dark-mode {
    background-color: #121212;
    color: #fff;
}

.container {
    background: var(--container-bg);
    padding: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    width: 300px;
    transition: background 0.3s, color 0.3s;
}

h1 {
    text-align: center;
}

form {
    display: flex;
    flex-direction: column;
}

input, select, button {
    margin-bottom: 10px;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
}

button {
    background: #28a745;
    color: #fff;
    border: none;
    cursor: pointer;
    transition: background 0.3s;
}

button:hover {
    background: #218838;
}

ul {
    list-style: none;
    padding: 0;
}

li {
    background: var(--list-item-bg);
    margin-bottom: 10px;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    transition: background 0.3s, color 0.3s;
}

.month-box {
    cursor: pointer;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    margin-bottom: 10px;
    background: var(--list-item-bg);
    transition: background 0.3s, color 0.3s;
}

.month-box:hover {
    background: var(--list-item-hover-bg);
}

/* Modal styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0, 0, 0, 0.4);
    padding-top: 60px;
}

.modal-content {
    background-color: var(--modal-bg);
    margin: 5% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    position: relative;
    transition: background 0.3s, color 0.3s;
}

.close-button {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
}

.close-button:hover,
.close-button:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
}

:root {
    --container-bg: #fff;
    --list-item-bg: #f4f4f4;
    --list-item-hover-bg: #e0e0e0;
    --modal-bg: #fefefe;
}

body.dark-mode {
    --container-bg: #1e1e1e;
    --list-item-bg: #2c2c2c;
    --list-item-hover-bg: #3c3c3c;
    --modal-bg: #2c2c2c;
}

/* Theme toggle button styles */
#theme-toggle {
    position: absolute;
    top: 10px;
    right: 10px;
    padding: 10px 20px;
    background-color: #28a745;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.3s;
}

#theme-toggle:hover {
    background-color: #218838;
}