:root {
    --primary-color: #8b5cf6; 
    --primary-hover: #a855f7; 
    --bg-main: #18191c;
    --bg-card: #2b2d31;
    --text-main: #ffffff;
    --text-dim: #b5bac1;
    --border-color: rgba(255,255,255,0.05);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Roboto, sans-serif;
}

body {
    background-color: var(--bg-main);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
}

a {
    text-decoration: none;
    color: inherit;
}

/* --- HEADER --- */
.main-header {
    background-color: #1e1f22;
    padding: 15px 5%;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1400px;
    margin: 0 auto;
}

.logo .logo-top {
    font-size: 22px;
    font-weight: 800;
    color: #fff;
    letter-spacing: 1px;
}

.logo .logo-bottom {
    font-size: 16px;
    font-weight: 1000;
    color: var(--primary-color);
    margin-top: -1px;
}

.header-nav {
    display: flex;
    gap: 25px;
}

.header-nav a {
    color: var(--text-dim);
    font-size: 15px;
    font-weight: 600;
    transition: 0.3s;
}

.header-nav a:hover,
.header-nav a.active {
    color: #fff;
    text-shadow: 0 0 10px var(--primary-color);
}

.header-icons {
    display: flex;
    gap: 15px;
    font-size: 18px;
    cursor: pointer;
}

/* --- CHAT LAYOUT WRAPPER --- */
.chat-wrapper {
    flex: 1;
    display: flex;
    justify-content: center;
    padding: 30px 2%; 
}

.chat-layout {
    display: flex;
    width: 100%; 
    max-width: 1600px; 
    height: 85vh; 
    background-color: var(--bg-card);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 50px rgba(0,0,0,0.5);
}

/* --- SIDEBAR LEFT --- */
.site-footer {
    background-color: #111214;
    padding: 60px 0;
    margin-top: 40px;
}

.sidebar-header {
    padding: 20px;
    font-size: 16px;
    font-weight: bold;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-main);
}

.sidebar-topics {
    width: 280px;
    background-color: rgba(0,0,0,0.2);
    display: flex;
    flex-direction: column;
    padding: 15px 0;
}

.topic-list {
    list-style: none;
    overflow-y: auto;
    flex: 1;
    padding: 10px 0;
}

.topic-item {
    padding: 12px 20px;
    color: var(--text-dim);
    margin: 2px 10px;
    border-radius: 8px;
    cursor: pointer;
    transition: 0.2s;
}

.topic-item:hover, .topic-item.active {
    background-color: var(--primary-color);
    color: #fff !important; 
}

/* --- MAIN CHAT AREA --- */
.main-chat {
    flex: 1;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-main);
    border-left: 1px solid var(--border-color);
    border-right: 1px solid var(--border-color);
}

.chat-header {
    padding: 15px 20px;
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    font-weight: bold;
}

.chat-header span {
    color: var(--text-dim);
    font-size: 13px;
    margin-left: 10px;
    font-weight: normal;
}

#chat-messages {
    flex: 1; /* Để nó chiếm hết không gian ở giữa */
    overflow-y: auto; /* Tạo thanh cuộn khi tin nhắn quá dài */
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px; /* Khoảng cách giữa các tin nhắn */
    background-color: #313338; /* Màu nền tối giống Discord */
}

#chat-messages::-webkit-scrollbar {
    width: 8px;
}

#chat-messages::-webkit-scrollbar-thumb {
    background: #1e1f22;
    border-radius: 4px;
}

.message-box {
    display: flex;
    gap: 15px;
}

.message-box .avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.message-info .username {
    font-weight: bold;
    color: var(--primary-color);
    margin-right: 10px;
}

.message-info .time {
    font-size: 12px;
    color: var(--text-dim);
}

.message-text {
    color: var(--text-main);
    margin-top: 5px;
    line-height: 1.5;
}

/* --- INPUT AREA --- */
.chat-input-area {
    padding: 20px;
    background-color: var(--bg-card);
}

.input-wrapper {
    display: flex;
    background-color: var(--bg-main);
    border-radius: 8px;
    padding: 10px 15px;
}

.input-wrapper input {
    flex: 1;
    background: transparent;
    border: none;
    color: #fff;
    outline: none;
}

.input-wrapper button {
    background: var(--primary-color);
    color: #fff;
    border: none;
    padding: 8px 15px;
    border-radius: 5px;
    cursor: pointer;
}

/* --- SIDEBAR RIGHT - bạn bè --- */
.sidebar-friends {
    width: 240px;
    background-color: var(--bg-card);
    border-left: 1px solid var(--border-color);
}

.friend-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 20px;
    cursor: pointer;
}

.friend-avatar {
    width: 35px;
    height: 35px;
    border-radius: 50%;
    position: relative;
    background: #444;
}

.status-dot {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    border: 2px solid var(--bg-card);
}

.status-dot.online {
    background: #2ecc71;
}

.status-dot.offline {
    background: #95a5a6;
}

.friend-name {
    color: var(--text-dim);
    font-size: 14px;
}

/* --- FOOTER --- */
.site-footer {
    background-color: #1a1b1e;
    border-top: 1px solid #333;
    margin-top: auto;
}

.footer-top {
    text-align: center;
    padding: 20px;
    border-bottom: 1px solid #2a2b2e;
}

.footer-links a {
    color: #666;
    font-size: 13px;
    margin: 0 10px;
}

.footer-main {
    padding: 20px 5%;
}

.footer-container {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    max-width: 1200px;
    margin: 0 auto;
}

.footer-logo {
    font-size: 28px;
    font-weight: 900;
    color: #3b82f6;
}

.footer-logo span {
    color: #fff;
}

.footer-info h3 {
    color: #fff;
    font-size: 16px;
    margin-bottom: 10px;
    border-bottom: 2px solid var(--primary-color);
    display: inline-block;
}

.footer-tags a {
    display: inline-block;
    padding: 4px 12px;
    background: #2b2d31;
    border: 1px solid #444;
    border-radius: 4px;
    margin: 5px;
    font-size: 12px;
    color: var(--text-dim);
}

.footer-bottom {
    background: #111214;
    padding: 15px;
    text-align: center;
    color: #444;
    font-size: 12px;
}

::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-thumb {
    background: #444;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

/* --- SEARCH BAR --- */
.search-container {
    display: flex;
    align-items: center;
    background: #111214;
    border-radius: 20px;
    padding: 5px 15px;
    border: 1px solid #444;
}

#global-search {
    background: transparent;
    border: none;
    color: white;
    outline: none;
    width: 150px;
}

#btn-search-trigger {
    background: transparent;
    border: none;
    color: var(--text-dim);
    cursor: pointer;
}