:root {
    --theme-color: #8f91ea;
    --timestamp-color: #b5b5b5;
    --status-online: #28a745;
    --status-offline: #888888;
    --bg-gradient: linear-gradient(135deg, #121212, #1c1c1c);
    --bg-color: #121212;
    --text-color: #f5f5f5;
    --menu-bg: #1c1c1c;
    --menu-text-color: #8f91ea;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --icon-color: invert(100%);
    --highlight-color: #8f91ea;
    --friend-item-hover: #2b2b2b;
    --btn-text-color: #ffffff;
    --btn-bg: linear-gradient(135deg, #6a75c9, #5a67c8);
    --btn-bg-hover: linear-gradient(135deg, #5a67c8, #4854c8);
    --btn-bg-danger: linear-gradient(135deg, #e57373, #c0392b);
    --btn-bg-danger-hover: linear-gradient(135deg, #c0392b, #96281b);
    --scrollbar-thumb: #444444;
    --scrollbar-track: #1c1c1c;
    --bg-slider-color: rgba(143, 145, 234, 0.1);
    --switch-slider: #555555;
    --switch-slider-before: #ffffff;
    --switch-slider-checked: #8f91ea;
}

[data-theme='light'] {
    --theme-color: #8f91ea;
    --timestamp-color: #6c757d;
    --status-online: #28a745;
    --status-offline: #adb5bd;
    --bg-gradient: linear-gradient(135deg, #ffffff, #f4f4f4);
    --bg-color: #ffffff;
    --text-color: #212529;
    --menu-bg: #e9ecef;
    --menu-text-color: #8f91ea;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --icon-color: none;
    --highlight-color: #8f91ea;
    --friend-item-hover: #f1f3f5;
    --btn-text-color: #ffffff;
    --btn-bg: linear-gradient(135deg, #6a75c9, #5a67c8);
    --btn-bg-hover: linear-gradient(135deg, #5a67c8, #4854c8);
    --btn-bg-danger: linear-gradient(135deg, #e57373, #c0392b);
    --btn-bg-danger-hover: linear-gradient(135deg, #c0392b, #96281b);
    --scrollbar-thumb: #cccccc;
    --scrollbar-track: #f7f7f7;
    --bg-slider-color: rgba(143, 145, 234, 0.1);
    --switch-slider: #cccccc;
    --switch-slider-before: #ffffff;
    --switch-slider-checked: #8f91ea;
}

::-webkit-scrollbar {
    width: 5px;
}

::-webkit-scrollbar-thumb {
    background-color: var(--scrollbar-thumb);
    border-radius: 50px;
}

::-webkit-scrollbar-track {
    background-color: var(--scrollbar-track);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html,
body {
    font-family: 'Roboto', sans-serif;
    background: var(--bg-gradient);
    color: var(--text-color);
    height: 100%;
}

.main_box {
    display: flex;
    justify-content: center;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 450px;
    background-color: var(--menu-bg);
    padding: 15px;
    box-shadow: 0 2px 8px var(--shadow-color);
    position: relative;
}

.header h1 {
    color: var(--text-color);
    font-size: 18px;
    text-align: center;
    flex: 1;
    margin: 0;
}

.header button {
    background: transparent;
    border: none;
    color: var(--text-color);
    cursor: pointer;
}

.header button img {
    width: 24px;
    height: 24px;
    filter: var(--icon-color);
}

.menu {
    position: relative;
}

.menu button {
    background: transparent;
    border: none;
    cursor: pointer;
}

.dropdown-content {
    display: none;
    position: absolute;
    right: 0;
    top: 40px;
    background-color: var(--menu-bg);
    min-width: 160px;
    box-shadow: 0 8px 16px var(--shadow-color);
    z-index: 1;
    border-radius: 5px;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.dropdown-content a {
    color: var(--text-color);
    padding: 10px 15px;
    text-decoration: none;
    border-radius: 5px;
    display: block;
    font-size: 16px;
}

.dropdown-content a:hover {
    background-color: var(--highlight-color);
    border-radius: 5px;
    color: var(--bg-color);
}

.dropdown-content.show {
    display: block;
    border-radius: 5px;
    opacity: 1;
}

.btn {
    background: var(--btn-bg);
    color: var(--btn-text-color);
    padding: 6px 15px;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
    transition: background 0.3s ease, transform 0.2s ease;
}

.btn:hover {
    background: var(--btn-bg-hover);
    transform: scale(1.02);
}

.chat_box {
    background: var(--bg-color);
    width: 100%;
    max-width: 450px;
    max-height: 900px;
    display: flex;
    height: calc(var(--vh, 1vh) * 100);
    flex-direction: column;
    box-shadow: 0 8px 16px var(--shadow-color);
}

.chat-area {
    flex: 1;
    padding: 10px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.chat-message {
    display: flex;
    flex-direction: column;
    max-width: 70%;
}

.chat-message.sent {
    align-self: flex-end;
    text-align: right;
}

.chat-message.received {
    align-self: flex-start;
    text-align: left;
}

.message-text {
    background-color: var(--menu-bg);
    color: var(--text-color);
    padding: 10px 15px;
    border-radius: 10px;
    word-wrap: break-word;
    line-height: 1.5;
    text-align: left;
}

.timestamp {
    font-size: 12px;
    color: var(--timestamp-color);
    margin-top: 4px;
}

.input-area {
    display: flex;
    align-items: center;
    border-radius: 30px;
}

.message-input {
    flex: 1;
    background-color: var(--menu-bg);
    color: var(--text-color);
    border: 8px solid var(--menu-bg);
    resize: none;
    outline: none;
    border-radius: 20px;
    height: 46px;
    max-height: 110px;
    overflow-y: auto;
    line-height: 20px;
    padding: 5px 15px;
    margin: 10px 0px 10px 10px;
}

.send-button {
    margin: 10px 10px 10px 5px;
    padding: 5px 12px 6px 12px;
    border: none;
    border-radius: 50%;
    background: var(--btn-bg);
    color: var(--btn-text-color);
    cursor: pointer;
    font-size: 25px;
    transition: background 0.3s ease, transform 0.2s ease;
}

.send-button:hover {
    background: var(--btn-bg-hover);
    transform: scale(1.02);
}