/* ════════════════════════════════════════════════
   Chat Application — Design System
   ════════════════════════════════════════════════ */

/* ── Custom Properties ──────────────────────── */
:root {
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', monospace;

    --color-primary: #007bff;
    --color-primary-hover: #0056b3;
    --color-danger: #dc3545;
    --color-danger-hover: #c82333;
    --color-success: #28a745;
    --color-success-hover: #218838;
    --color-warning: #ffc107;
    --color-info: #17a2b8;

    --color-bg-primary: #f0f4f8;
    --color-bg-secondary: #f8f9fa;
    --color-bg-card: #ffffff;
    --color-bg-hover: #e9ecef;
    --color-text-primary: #212529;
    --color-text-secondary: #6c757d;
    --color-text-muted: #adb5bd;
    --color-text-inverse: #ffffff;
    --color-border: #dee2e6;
    --color-border-strong: #adb5bd;

    --color-message-own: #007bff;
    --color-message-other: #f1f3f5;

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;
    --radius-full: 50%;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.16);

    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;

    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 12px;
    --space-lg: 16px;
    --space-xl: 20px;
    --space-2xl: 24px;
    --space-3xl: 32px;
    --space-4xl: 48px;

    --sidebar-width: 260px;
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-modal: 500;
    --z-toast: 1000;
    --z-tooltip: 1100;
}

/* ── Base ───────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

body {
    background: linear-gradient(135deg, #83a4d4, #b6fbff);
    min-height: 100vh;
    margin: 0;
    font-family: var(--font-sans);
    color: var(--color-text-primary);
    -webkit-font-smoothing: antialiased;
}

.hidden { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }

/* ── Layout ─────────────────────────────────── */
.container {
    display: flex;
    max-width: 1200px;
    margin: var(--space-xl) auto;
    background: var(--color-bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    height: calc(100vh - 40px);
}

/* ── Icons ──────────────────────────────────── */
.material-icons { font-size: 20px; line-height: 1; vertical-align: middle; }

/* ── Connection Status ─────────────────────── */
.connection-status {
    position: fixed;
    top: 0; left: 0; right: 0;
    height: 4px;
    z-index: var(--z-tooltip);
    transition: background var(--transition-normal);
}
.connection-status.status-connected { background: var(--color-success); }
.connection-status.status-reconnecting { background: var(--color-warning); height: 24px; color: #333; text-align: center; font-size: 13px; line-height: 24px; }
.connection-status.status-disconnected { background: var(--color-danger); height: 24px; color: #fff; text-align: center; font-size: 13px; line-height: 24px; }

/* ── Toast Notifications ────────────────────── */
.toast-container {
    position: fixed;
    top: var(--space-lg);
    right: var(--space-lg);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    pointer-events: none;
    max-width: 400px;
}
.toast {
    background: var(--color-bg-card);
    border-radius: var(--radius-sm);
    padding: var(--space-md) var(--space-lg);
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--color-info);
    font-size: 14px;
    pointer-events: auto;
    transform: translateX(120%);
    opacity: 0;
    transition: transform var(--transition-normal), opacity var(--transition-normal);
}
.toast.visible { transform: translateX(0); opacity: 1; }
.toast-success { border-color: var(--color-success); }
.toast-error { border-color: var(--color-danger); }
.toast-warning { border-color: var(--color-warning); }

/* ── Sidebar ────────────────────────────────── */
.sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    background: var(--color-bg-secondary);
    border-right: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    padding: 0 var(--space-lg);
}
.sidebar-toggle { display: none; }
.sidebar-header {
    padding: var(--space-lg) 0;
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    background: var(--color-bg-secondary);
    z-index: var(--z-sticky);
}
.sidebar-header span { font-weight: 600; font-size: 14px; }

/* ── Buttons ────────────────────────────────── */
.logout-btn { color: var(--color-danger); background: transparent; border: none; border-radius: var(--radius-sm); cursor: pointer; padding: var(--space-sm); }
.logout-btn:hover { transform: scale(1.1); }
.logout-btn .material-icons { font-size: 24px; }

.btn-primary { background: var(--color-primary); color: #fff; border: none; border-radius: var(--radius-sm); padding: var(--space-sm) var(--space-lg); cursor: pointer; }
.btn-primary:hover { background: var(--color-primary-hover); }
.btn-secondary { background: var(--color-bg-secondary); color: var(--color-text-primary); border: 1px solid var(--color-border); border-radius: var(--radius-sm); padding: var(--space-sm) var(--space-lg); cursor: pointer; }
.btn-danger { background: var(--color-danger); color: #fff; border: none; border-radius: var(--radius-sm); padding: var(--space-sm) var(--space-lg); cursor: pointer; }
.btn-danger:hover { background: var(--color-danger-hover); }

/* ── Room List ──────────────────────────────── */
.room-creation { padding: var(--space-md) 0 var(--space-lg); border-bottom: 1px solid var(--color-border); }
.room-creation input { width: 100%; padding: var(--space-sm); margin-bottom: var(--space-sm); border: 1px solid var(--color-border); border-radius: var(--radius-sm); font-size: 13px; }
.room-creation button { width: 100%; padding: var(--space-sm); background: var(--color-success); color: #fff; border: none; border-radius: var(--radius-sm); cursor: pointer; font-size: 13px; }
.room-creation button:hover { background: var(--color-success-hover); }

#room_list h3, #user_list h3 { font-size: 13px; color: var(--color-text-secondary); text-transform: uppercase; letter-spacing: 0.5px; margin: var(--space-md) 0 var(--space-sm); }

.room {
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    margin-bottom: var(--space-sm);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--color-bg-card);
    transition: background var(--transition-fast);
    font-size: 14px;
}
.room:hover, .room:focus-visible { background: var(--color-bg-hover); outline: none; box-shadow: 0 0 0 2px var(--color-primary); }
.room.current { background: #e3f2fd; border-color: #90caf9; }
.room-controls { display: flex; align-items: center; gap: var(--space-sm); }
.room-controls .material-icons { font-size: 16px; color: var(--color-text-secondary); }
.delete-room-btn { background: var(--color-danger); border: none; color: #fff; cursor: pointer; padding: 2px 8px; border-radius: var(--radius-sm); font-size: 12px; }
.delete-room-btn:hover { background: var(--color-danger-hover); }

/* ── User List ──────────────────────────────── */
.user-item {
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    cursor: pointer;
    transition: background var(--transition-fast);
    font-size: 14px;
}
.user-item:hover, .user-item:focus-visible { background: var(--color-bg-hover); outline: none; box-shadow: 0 0 0 2px var(--color-primary); }
.user-item.current-user { background: #ececec; border-color: #a1a1a1; font-weight: 600; }
.user-controls { display: flex; gap: var(--space-xs); margin-left: auto; }
.user-controls button { background: transparent; border: none; cursor: pointer; padding: 2px 4px; color: var(--color-text-secondary); border-radius: var(--radius-sm); }
.user-controls button:hover { color: var(--color-danger); }

.online-dot { width: 8px; height: 8px; border-radius: var(--radius-full); flex-shrink: 0; }
.online-dot.online { background: var(--color-success); }
.online-dot.offline { background: var(--color-text-muted); }

/* ── Banned/Kicked Lists ────────────────────── */
#banned_users_list, #kicked_users_list { margin-top: var(--space-lg); padding: var(--space-md); background: var(--color-bg-secondary); border-radius: var(--radius-sm); display: none; }
#banned_users_list h4, #kicked_users_list h4 { margin: 0 0 var(--space-sm); color: var(--color-danger); font-size: 13px; }
.banned-user-item { display: flex; justify-content: space-between; align-items: center; padding: var(--space-xs) var(--space-sm); margin: var(--space-xs) 0; background: var(--color-bg-card); border-radius: var(--radius-sm); font-size: 13px; }

.unban-btn, .unkick-btn { background: var(--color-success); color: #fff; border: none; padding: 3px 8px; border-radius: var(--radius-sm); cursor: pointer; font-size: 12px; }
.unban-btn:hover, .unkick-btn:hover { background: var(--color-success-hover); }

/* ── Kick Form ──────────────────────────────── */
.kick-form { display: flex; gap: var(--space-sm); align-items: center; padding: var(--space-sm); font-size: 13px; }
.kick-form input { width: 60px; padding: 2px 4px; border: 1px solid var(--color-border); border-radius: var(--radius-sm); }
.kick-form button { padding: 2px 8px; border: none; border-radius: var(--radius-sm); cursor: pointer; font-size: 12px; }
.kick-confirm { background: var(--color-warning); color: #333; }
.kick-cancel { background: var(--color-bg-secondary); border: 1px solid var(--color-border) !important; }

/* ── Chat Area ──────────────────────────────── */
.chat-container { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

/* ── Chat Tabs ──────────────────────────────── */
.chat-tabs {
    background: var(--color-bg-secondary);
    border-bottom: 2px solid var(--color-border);
    padding: 0 var(--space-xl);
    display: flex;
    overflow-x: auto;
    scrollbar-width: thin;
    flex-shrink: 0;
}
.chat-tab {
    padding: var(--space-md) var(--space-xl);
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    color: var(--color-text-secondary);
    cursor: pointer;
    white-space: nowrap;
    transition: all var(--transition-fast);
    position: relative;
    font-size: 14px;
}
.chat-tab:hover { background: var(--color-bg-hover); color: var(--color-text-primary); }
.chat-tab.active, .chat-tab[aria-selected="true"] { background: var(--color-bg-card); color: var(--color-primary); border-bottom-color: var(--color-primary); }
.chat-tab:focus-visible { outline: 2px solid var(--color-primary); outline-offset: -2px; }

.tab-close { margin-left: var(--space-sm); opacity: 0.6; cursor: pointer; display: inline-flex; align-items: center; }
.tab-close:hover { opacity: 1; }
.tab-close .material-icons { font-size: 16px; }

.unread-badge {
    position: absolute; top: 4px; right: 4px;
    background: var(--color-danger); color: #fff;
    border-radius: var(--radius-full);
    min-width: 18px; height: 18px;
    font-size: 11px; line-height: 18px; text-align: center;
    padding: 0 4px;
}
.unread-badge.hidden { display: none; }

/* ── Chat Messages ──────────────────────────── */
#chatlog, .private-chat {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-xl);
    background: var(--color-bg-card);
    scroll-behavior: smooth;
}
.room-chat.hidden { display: none; }
.private-chat { display: none; height: 100%; }
.private-chat.active { display: flex; flex-direction: column; }
#private-chats { flex: 1; display: flex; flex-direction: column; }

.message {
    margin-bottom: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-lg);
    max-width: 75%;
    word-wrap: break-word;
    position: relative;
    font-size: 14px;
    line-height: 1.5;
    animation: messageIn 0.2s ease;
}
@keyframes messageIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }

.message-own { background: var(--color-message-own); color: var(--color-text-inverse); margin-left: auto; border-bottom-right-radius: var(--radius-sm); }
.message-other { background: var(--color-message-other); color: var(--color-text-primary); margin-right: auto; border-bottom-left-radius: var(--radius-sm); }
.system-message { background: #fff3cd; color: #856404; max-width: 100%; text-align: center; font-style: italic; font-size: 12px; margin: var(--space-sm) 0; padding: var(--space-xs) var(--space-md); border-radius: var(--radius-sm); }

.message .controls {
    position: absolute; top: 50%; right: var(--space-sm); transform: translateY(-50%);
    display: flex; gap: 4px; opacity: 0; transition: opacity var(--transition-fast);
}
.message:hover .controls { opacity: 1; }
.message .controls button { background: none; border: none; cursor: pointer; padding: 2px; color: inherit; opacity: 0.7; border-radius: var(--radius-sm); }
.message .controls button:hover { opacity: 1; }
.message .controls .material-icons { font-size: 16px; }

.msg-time { font-size: 11px; opacity: 0.7; margin-right: 4px; }
.msg-author { font-weight: 600; }

.reply-indicator { font-size: 12px; opacity: 0.8; margin-bottom: var(--space-xs); cursor: pointer; }
.reply-indicator:hover { opacity: 1; }
.message.reply { border-left: 3px solid var(--color-primary); }

.private-message { background: var(--color-message-other); color: var(--color-text-primary); padding: var(--space-sm) var(--space-md); border-radius: var(--radius-lg); margin-bottom: var(--space-sm); max-width: 75%; position: relative; font-size: 14px; }
.message-own.private-message { background: var(--color-message-own); color: var(--color-text-inverse); margin-left: auto; }

/* ── Empty State ────────────────────────────── */
.empty-state { text-align: center; color: var(--color-text-muted); padding: var(--space-4xl) var(--space-xl); font-size: 15px; }

/* ── Date Separator ─────────────────────────── */
.date-separator {
    text-align: center;
    color: var(--color-text-muted);
    font-size: 12px;
    margin: var(--space-lg) 0;
    display: flex;
    align-items: center;
    gap: var(--space-md);
}
.date-separator::before, .date-separator::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--color-border);
}

/* ── Scroll Button ──────────────────────────── */
.scroll-bottom-btn {
    position: sticky; bottom: var(--space-sm);
    float: right; z-index: var(--z-sticky);
    width: 36px; height: 36px;
    border-radius: var(--radius-full);
    background: var(--color-primary); color: #fff; border: none;
    box-shadow: var(--shadow-md); cursor: pointer;
    font-size: 18px; display: flex; align-items: center; justify-content: center;
    transition: opacity var(--transition-fast), transform var(--transition-fast);
    margin-right: var(--space-sm);
}
.scroll-bottom-btn.hidden { opacity: 0; transform: scale(0.8); pointer-events: none; }

/* ── Message Input ──────────────────────────── */
.message-input-container {
    display: flex; flex-direction: column;
    padding: var(--space-md) var(--space-xl);
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    flex-shrink: 0;
}
.message-input-container > div:first-child { display: flex; align-items: center; }

.message-input-container textarea {
    flex: 1; padding: var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 14px; font-family: inherit;
    resize: none; outline: none;
    transition: border-color var(--transition-fast);
}
.message-input-container textarea:focus { border-color: var(--color-primary); }

.message-input-container button {
    background: transparent; border: none; cursor: pointer; color: var(--color-primary); padding: var(--space-sm); margin-left: var(--space-sm);
}
.message-input-container button:hover { transform: scale(1.1); }
.message-input-container button .material-icons { font-size: 24px; }

.typing-indicator { font-size: 12px; color: var(--color-text-secondary); font-style: italic; min-height: 18px; padding: 0 var(--space-md) var(--space-xs); }
.typing-indicator:not(:empty)::after { content: ''; animation: typingDots 1.4s infinite; }
@keyframes typingDots { 0%, 20% { content: ''; } 40% { content: '.'; } 60% { content: '..'; } 80%, 100% { content: '...'; } }

.replying-to {
    background: var(--color-bg-secondary); padding: var(--space-sm) var(--space-md);
    border-left: 3px solid var(--color-primary); margin-bottom: var(--space-sm);
    border-radius: var(--radius-sm); display: flex; justify-content: space-between; align-items: center;
    font-size: 12px; color: var(--color-text-secondary);
}
.cancel-reply { background: none; border: none; color: var(--color-text-secondary); cursor: pointer; }
.cancel-reply:hover { color: var(--color-text-primary); }

/* ── Login ──────────────────────────────────── */
.login-container {
    position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);
    background: var(--color-bg-card); padding: var(--space-4xl);
    border-radius: var(--radius-md); box-shadow: var(--shadow-lg);
    text-align: center; width: 90%; max-width: 360px;
}
.login-container h2 { color: #2c3e50; margin-bottom: var(--space-sm); font-size: 28px; }
.login-container p { color: #7f8c8d; margin-bottom: var(--space-2xl); font-size: 14px; }
.login-container input { width: 100%; padding: var(--space-md); margin-bottom: var(--space-xl); border: 2px solid var(--color-border); border-radius: var(--radius-sm); font-size: 14px; transition: border-color var(--transition-fast); }
.login-container input:focus { border-color: var(--color-primary); outline: none; }
.login-container button { width: 100%; padding: var(--space-md); background: var(--color-primary); color: #fff; border: none; border-radius: var(--radius-sm); font-size: 16px; cursor: pointer; }
.login-container button:hover { background: var(--color-primary-hover); }

/* ── Modals ─────────────────────────────────── */
.modal-overlay {
    position: fixed; inset: 0;
    background: rgba(0, 0, 0, 0.4); backdrop-filter: blur(4px);
    z-index: var(--z-modal); display: flex; align-items: center; justify-content: center;
}
.modal-content { background: var(--color-bg-card); padding: var(--space-2xl); border-radius: var(--radius-md); box-shadow: var(--shadow-lg); min-width: 320px; max-width: 90%; }
.modal-content h3 { margin: 0 0 var(--space-md); }
.modal-content input { width: 100%; padding: var(--space-md); border: 1px solid var(--color-border); border-radius: var(--radius-sm); margin-bottom: var(--space-lg); font-size: 14px; }
.modal-content input:focus { border-color: var(--color-primary); outline: none; }
.modal-sm { max-width: 360px; }
.modal-buttons { display: flex; gap: var(--space-sm); justify-content: flex-end; }

/* ── Focus Styles ───────────────────────────── */
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
button:focus-visible, input:focus-visible, textarea:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

/* ── Scrollbar ──────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-text-muted); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-text-secondary); }

/* ── Selection ──────────────────────────────── */
::selection { background: var(--color-primary); color: var(--color-text-inverse); }

/* ════════════════════════════════════════════════
   Mobile Responsive
   ════════════════════════════════════════════════ */
@media (max-width: 768px) {
    .container { flex-direction: column; height: 100vh; margin: 0; border-radius: 0; }
    .sidebar { width: 100%; min-width: 100%; max-height: 40vh; border-right: none; border-bottom: 1px solid var(--color-border); padding: 0 var(--space-md); }
    .sidebar-toggle { display: flex; align-items: center; justify-content: center; width: 40px; height: 40px; background: var(--color-bg-secondary); border: none; cursor: pointer; font-size: 20px; position: absolute; top: var(--space-sm); right: var(--space-sm); z-index: var(--z-sticky); border-radius: var(--radius-sm); }
    .sidebar.collapsed { max-height: 50px; overflow: hidden; }
    .sidebar.collapsed > *:not(.sidebar-toggle):not(.sidebar-header) { display: none; }
    .chat-container { flex: 1; }
    .message { max-width: 85%; }
    .message .controls { opacity: 1; position: static; transform: none; margin-top: var(--space-xs); }
    .login-container { width: 95%; padding: var(--space-2xl); }
    .toast-container { left: var(--space-sm); right: var(--space-sm); max-width: none; }
    .modal-content { min-width: auto; width: 95%; }
}

@media (max-width: 480px) {
    .message { max-width: 90%; font-size: 13px; }
    .message .controls { gap: 2px; }
    .chat-tab { padding: var(--space-sm) var(--space-md); font-size: 13px; }
    #chatlog, .private-chat { padding: var(--space-md); }
    .message-input-container { padding: var(--space-sm) var(--space-md); }
}

/* ── Touch devices ──────────────────────────── */
@media (hover: none) {
    .message .controls { opacity: 1; }
    .private-message .controls { opacity: 1; }
}

/* ── Reduced Motion ─────────────────────────── */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; scroll-behavior: auto !important; }
}

/* ── Print ──────────────────────────────────── */
@media print {
    body { background: #fff; }
    .container { box-shadow: none; }
    .sidebar, .message-input-container, .connection-status, .toast-container { display: none; }
}