.container {
    max-width: 1000px;
    margin: 0 auto;
    background-color: #121212;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.page-content h1 {
    text-align: center;
    color: #333;
}

.tabs {
    display: flex;
    margin-bottom: 20px;
    border-bottom: 1px solid #ddd;
}

.tab {
    padding: 10px 20px;
    cursor: pointer;
    background-color: #121212;
    border: 1px solid #ddd;
    border-bottom: none;
    border-radius: 5px 5px 0 0;
    margin-right: 5px;
}

.tab.active {
    background-color: #737373;
    border-bottom: 1px solid white;
    margin-bottom: -1px;
}

.tab-content {
    display: none;
    padding: 20px;
    border: 1px solid #ddd;
    border-top: none;
    border-radius: 0 0 5px 5px;
}

.tab-content.active {
    display: block;
}

.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

input:not(input[type="checkbox"]), select {
    width: 100%;
}

input, select {
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-sizing: border-box;
}

.page-content button {
    padding: 10px 15px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    margin-right: 10px;
}

.page-content button:hover {
    background-color: #45a049;
}

.person-list {
    max-height: 300px;
    overflow-y: auto;
    border: 1px solid #ddd;
    padding: 10px;
    margin-bottom: 15px;
}

.person-item {
    padding: 8px;
    border-bottom: 1px solid #eee;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.person-item:last-child {
    border-bottom: none;
}

.person-item button {
    padding: 5px 10px;
    font-size: 12px;
}

.person-checkbox {
    margin-right: 10px;
}

.selected-people {
    margin-top: 20px;
    padding: 10px;
    background-color: #121212;
    border-radius: 4px;
}

.selected-person {
    display: inline-block;
    padding: 5px 10px;
    background-color: #121212;
    border-radius: 3px;
    margin-right: 5px;
    margin-bottom: 5px;
}

.selected-person button {
    background: none;
    border: none;
    color: #ff4d4d;
    cursor: pointer;
    padding: 0 5px;
    font-size: 14px;
}

.group-list {
    margin-top: 20px;
}

.group-item {
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 4px;
    margin-bottom: 10px;
    background-color: #222222;
}

.group-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
}

.group-name {
    font-weight: bold;
    font-size: 18px;
}

.group-period {
    color: #666;
}

.group-members {
    font-size: 14px;
}

.member-tag {
    display: inline-block;
    padding: 3px 8px;
    background-color: #121212;
    border-radius: 3px;
    margin-right: 5px;
    margin-bottom: 5px;
}

.loading {
    padding: 10px;
    text-align: center;
    color: #666;
}

.error {
    padding: 10px;
    text-align: center;
    color: #ff4d4d;
}

.empty {
    padding: 10px;
    text-align: center;
    color: #888;
    font-style: italic;
}

.empty-selection {
    padding: 5px;
    color: #888;
    font-style: italic;
}