body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    background-color: #f4f4f4;
    color: #333;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    width: 80%;
    max-width: 900px;
    display: flex;
    flex-direction: column;
}

header {
    background-color: #5c6bc0;
    color: #fff;
    padding: 20px;
    text-align: center;
}

main {
    display: flex;
    flex-grow: 1;
}

#login-section {
    padding: 30px;
    text-align: center;
}

#login-section input[type="text"] {
    padding: 10px;
    margin-bottom: 15px;
    border: 1px solid #ccc;
    border-radius: 4px;
    width: 80%;
    max-width: 300px;
}

#login-section button {
    padding: 10px 20px;
    background-color: #5c6bc0;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
}

#chat-section {
    display: flex;
    flex-grow: 1;
}

#group-list {
    background-color: #eee;
    padding: 20px;
    width: 200px;
    border-right: 1px solid #ddd;
}

#group-list h2 {
    margin-top: 0;
    margin-bottom: 15px;
    color: #555;
}

#group-list ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

#group-list ul li {
    margin-bottom: 10px;
}

#group-list ul li button {
    background-color: #f0f0f0;
    border: 1px solid #ccc;
    border-radius: 4px;
    padding: 8px 12px;
    cursor: pointer;
    width: 100%;
    text-align: left;
    color: #333;
    font-size: 14px;
}

#group-list ul li button:hover {
    background-color: #e0e0e0;
}

#chat-window {
    flex-grow: 1;
    padding: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

#messages {
    flex-grow: 1;
    overflow-y: auto;
    padding-bottom: 15px;
}

.message {
    background-color: #f9f9f9;
    border: 1px solid #eee;
    border-radius: 6px;
    padding: 10px;
    margin-bottom: 10px;
    word-break: break-word;
}

.message strong {
    font-weight: bold;
    color: #5c6bc0;
    margin-right: 5px;
}

#input-area {
    display: flex;
}

#message-input {
    flex-grow: 1;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px 0 0 4px;
}

#send-button {
    padding: 10px 15px;
    background-color: #5c6bc0;
    color: #fff;
    border: none;
    border-radius: 0 4px 4px 0;
    cursor: pointer;
    font-size: 16px;
}

footer {
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 10px;
}

.modal {
    display: none; /* Başlangıçta gizli */
    position: fixed; /* Ekran üzerinde sabit durur */
    z-index: 1; /* Diğer elementlerin üzerinde görünür */
    left: 0;
    top: 0;
    width: 100%; /* Tam genişlik */
    height: 100%; /* Tam yükseklik */
    overflow: auto; /* İçerik taşarsa kaydırma çubuğu gösterir */
    background-color: rgba(0,0,0,0.4); /* Siyah arka plan ve saydamlık */
}

.modal-content {
    background-color: #fefefe;
    margin: 15% auto; /* Ekranın ortasına yakın konumlanır */
    padding: 20px;
    border: 1px solid #888;
    width: 80%; /* Genişliğin %80'i */
    border-radius: 8px;
    position: relative;
}

.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;
}

.modal-content h2 {
    margin-top: 0;
    margin-bottom: 15px;
    color: #555;
    text-align: center;
}

.modal-content input[type="text"] {
    padding: 10px;
    margin-bottom: 15px;
    border: 1px solid #ccc;
    border-radius: 4px;
    width: 100%;
    box-sizing: border-box;
}

.modal-content button {
    padding: 10px 20px;
    background-color: #5c6bc0;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    width: 100%;
}

.modal-content button:hover {
    background-color: #4a59a3;
}