body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header {
    background-color: #333;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}

main {
    padding: 1rem;
}

#shas-container {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.seder {
    background-color: #fff;
    border: 1px solid #ddd;
    padding: 1rem;
    border-radius: 5px;
}

.masechet {
    margin-top: 1rem;
}

.units-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.unit {
    padding: 1rem;
    border: 1px solid #ccc;
    border-radius: 5px;
    text-align: center;
    cursor: pointer;
    transition: background-color 0.3s;
    position: relative; /* For positioning the indicator */
}

.unit.available {
    background-color: #e8f5e9; /* Light Green */
}

.unit.available:hover {
    background-color: #c8e6c9;
}

.unit.taken {
    background-color: #ffebee; /* Light Red */
    cursor: not-allowed;
}

.unit.completed {
    background-color: #e3f2fd; /* Light Blue */
    cursor: not-allowed;
}

.unit.is-hard {
    border: 2px solid #ffab40; /* Orange border */
}

.hard-unit-indicator {
    font-weight: bold;
    color: #c56200;
    margin: 0.5rem 0 0;
}


.unit h4 {
    margin-top: 0;
}

footer {
    text-align: center;
    padding: 1rem 0;
    margin-top: 2rem;
    background-color: #333;
    color: #fff;
}

/* Modal Styles */
.modal {
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.4);
}

.modal-content {
    background-color: #fefefe;
    margin: 15% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    border-radius: 5px;
    text-align: right;
}

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

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

#register-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

#register-form input,
#register-form button {
    padding: 10px;
    font-size: 1rem;
}