body {
    font-family: "Vazirmatn", Tahoma, sans-serif;
    background: linear-gradient(135deg, #4f8cfb, #2355b3 80%);
    min-height: 100vh;
    margin: 0;
}
.chat-container {
    max-width: 400px;
    margin: 5vh auto;
    background: #fff8;
    border-radius: 20px;
    box-shadow: 0 8px 24px #0002;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.login-form, .msg-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.login-form input, .msg-form input {
    padding: 10px;
    border-radius: 12px;
    border: 1px solid #bbd;
    outline: none;
}
.login-form button, .msg-form button, .logout {
    padding: 8px 20px;
    border-radius: 12px;
    background: #2355b3;
    color: #fff;
    font-weight: bold;
    border: none;
    cursor: pointer;
    transition: background .2s;
}
.login-form button:hover, .msg-form button:hover, .logout:hover {
    background: #4f8cfb;
}
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
}
.chat-box {
    background: #f7fafc;
    border-radius: 14px;
    padding: 10px 8px;
    height: 320px;
    overflow-y: auto;
    border: 1px solid #d7e5f7;
    font-size: 15px;
}
.user { color: #2355b3; font-weight: bold; }
.time { color: #bbb; font-size: 12px; margin: 0 4px; }
.msg { color: #444; }

::-webkit-scrollbar { width: 8px; background: #eee; border-radius: 10px; }
::-webkit-scrollbar-thumb { background: #aac; border-radius: 10px; }