* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
}

body {
    background-color: #f4f6f9;
}

.header {
    background-color: #fff;
    padding: 15px 20px;
    border-bottom: 1px solid #ddd;
    margin-bottom: 20px;
}

.header h1 {
    font-size: 18px;
    color: #333;
}

.container {
    display: flex;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
    gap: 20px;
    height: calc(100vh - 100px);
}

/* Khu vực Video */
.video-section {
    flex: 7;
    background: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* Tỉ lệ 16:9 */
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.video-info {
    padding: 20px;
}

/* Khu vực Chat */
.chat-section {
    flex: 3;
    background: #fff;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.chat-header {
    padding: 15px;
    border-bottom: 1px solid #eee;
    text-align: center;
}

.chat-messages {
    flex: 1;
    padding: 15px;
    overflow-y: auto;
    background: #fafafa;
}

.message {
    margin-bottom: 15px;
    padding: 10px;
    background: #fff;
    border-radius: 5px;
    border-left: 3px solid #007bff;
    font-size: 14px;
    line-height: 1.5;
}

.chat-input {
    display: flex;
    padding: 15px;
    border-top: 1px solid #eee;
}

.chat-input input {
    flex: 1;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    outline: none;
}

.chat-input button {
    padding: 10px 20px;
    margin-left: 10px;
    background: #007bff;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

.chat-input button:hover {
    background: #0056b3;
}