*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg: #e5ddd5;
    --sidebar-bg: #fff;
    --sidebar-border: #ddd;
    --bubble-self: #dcf8c6;
    --bubble-other: #fff;
    --bubble-system: #f0f0f0;
    --text: #111;
    --text-secondary: #667;
    --header-bg: #075e54;
    --header-text: #fff;
    --accent: #25d366;
    --hover: #f5f5f5;
    --active: #e8f5e9;
    --shadow: rgba(0,0,0,0.08);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0b141a;
        --sidebar-bg: #111b21;
        --sidebar-border: #2a3942;
        --bubble-self: #005c4b;
        --bubble-other: #202c33;
        --bubble-system: #182229;
        --text: #e9edef;
        --text-secondary: #8696a0;
        --header-bg: #1f2c34;
        --header-text: #e9edef;
        --hover: #2a3942;
        --active: #2a3942;
        --shadow: rgba(0,0,0,0.3);
    }
}

html, body {
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 14px;
    color: var(--text);
    background: var(--bg);
}

#app {
    display: flex;
    height: 100vh;
}

/* Sidebar */
#sidebar {
    width: 320px;
    min-width: 260px;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--sidebar-border);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

#sidebar-header {
    background: var(--header-bg);
    color: var(--header-text);
    padding: 14px 16px;
}

#sidebar-header h1 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 10px;
}

#search-box { margin-top: 0; }

#search-input {
    width: 100%;
    padding: 6px 12px;
    border: none;
    border-radius: 18px;
    font-size: 13px;
    outline: none;
    background: rgba(255,255,255,0.2);
    color: var(--header-text);
}

#search-input::placeholder {
    color: rgba(255,255,255,0.6);
}

#conversation-list {
    overflow-y: auto;
    flex: 1;
}

.conv-item {
    padding: 12px 16px;
    cursor: pointer;
    border-bottom: 1px solid var(--sidebar-border);
    transition: background 0.15s;
}

.conv-item:hover { background: var(--hover); }
.conv-item.active { background: var(--active); }

.conv-item .conv-name {
    font-weight: 600;
    font-size: 15px;
    margin-bottom: 2px;
}

.conv-item .conv-meta {
    font-size: 12px;
    color: var(--text-secondary);
}

/* Chat pane */
#chat-pane {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

#chat-header {
    background: var(--header-bg);
    color: var(--header-text);
    padding: 10px 16px;
    display: flex;
    align-items: center;
    gap: 16px;
    flex-shrink: 0;
}

#chat-name {
    font-weight: 600;
    font-size: 16px;
    white-space: nowrap;
}

#search-nav {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 6px;
}

#search-nav.hidden { display: none; }

#search-nav button {
    background: rgba(255,255,255,0.2);
    border: none;
    color: var(--header-text);
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
}

#search-nav button:hover { background: rgba(255,255,255,0.3); }

#search-pos {
    font-size: 13px;
    min-width: 40px;
    text-align: center;
}

#chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 16px;
    background: var(--bg);
}

.search-match {
    outline: 2px solid #ffeb3b88;
    outline-offset: 2px;
}

.search-match.search-current {
    outline: 2px solid #ff9800;
    outline-offset: 2px;
}

@media (prefers-color-scheme: dark) {
    .search-match { outline-color: #7c6f0088; }
    .search-match.search-current { outline-color: #ff9800; }
}

/* Date headers */
.date-header {
    text-align: center;
    margin: 16px 0 8px;
}

.date-header span {
    background: var(--bubble-system);
    color: var(--text-secondary);
    font-size: 12px;
    padding: 4px 12px;
    border-radius: 8px;
    display: inline-block;
    box-shadow: 0 1px 1px var(--shadow);
}

/* Message bubbles */
.message {
    max-width: 65%;
    margin: 2px 0;
    padding: 6px 10px;
    border-radius: 8px;
    position: relative;
    word-wrap: break-word;
    overflow-wrap: break-word;
    box-shadow: 0 1px 1px var(--shadow);
    clear: both;
}

.message.self {
    background: var(--bubble-self);
    margin-left: auto;
    border-top-right-radius: 2px;
}

.message.other {
    background: var(--bubble-other);
    margin-right: auto;
    border-top-left-radius: 2px;
}

.message.system {
    background: var(--bubble-system);
    color: var(--text-secondary);
    font-style: italic;
    font-size: 12px;
    text-align: center;
    max-width: 80%;
    margin: 8px auto;
    border-radius: 8px;
}

.message .sender-name {
    font-weight: 600;
    font-size: 12px;
    margin-bottom: 2px;
    color: var(--accent);
}

.message .msg-text {
    white-space: pre-wrap;
    line-height: 1.4;
}

.message .msg-time {
    font-size: 11px;
    color: var(--text-secondary);
    text-align: right;
    margin-top: 2px;
}

/* Media */
.msg-image {
    max-width: 300px;
    max-height: 300px;
    border-radius: 6px;
    cursor: pointer;
    display: block;
    margin: 4px 0;
}

.msg-sticker {
    width: 128px;
    height: 128px;
    object-fit: contain;
    display: block;
    margin: 4px 0;
}

.msg-video, .msg-audio {
    max-width: 300px;
    display: block;
    margin: 4px 0;
}

.msg-audio { width: 260px; }

.msg-document {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: rgba(0,0,0,0.05);
    border-radius: 8px;
    text-decoration: none;
    color: var(--text);
    margin: 4px 0;
    font-size: 13px;
}

.msg-document:hover { background: rgba(0,0,0,0.1); }

.msg-document::before {
    content: "\1F4CE";
    font-size: 18px;
}

/* Self selector */
#self-selector {
    padding: 8px 16px;
    background: var(--sidebar-bg);
    border-top: 1px solid var(--sidebar-border);
    font-size: 13px;
}

#self-name {
    padding: 4px 8px;
    font-size: 13px;
    border-radius: 4px;
    border: 1px solid var(--sidebar-border);
    background: var(--sidebar-bg);
    color: var(--text);
}

/* Lightbox */
.lightbox {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    cursor: zoom-out;
}

.lightbox.hidden { display: none; }

.lightbox img {
    max-width: 95vw;
    max-height: 95vh;
    object-fit: contain;
}

/* Search highlight */
mark {
    background: #ffeb3b;
    color: #000;
    border-radius: 2px;
    padding: 0 1px;
}

@media (prefers-color-scheme: dark) {
    mark {
        background: #7c6f00;
        color: #fff;
    }
}

/* Responsive */
@media (max-width: 600px) {
    #sidebar { width: 100%; position: absolute; z-index: 10; height: 100%; }
    #chat-pane { width: 100%; }
    .message { max-width: 85%; }
    #sidebar.hidden-mobile { display: none; }
}