/* Reset and Base Styles */
:root {
    /* Light Theme (Default) */
    --bg-body: #f5f7fa;
    --bg-surface: #ffffff;
    --bg-sidebar: #ffffff;
    --bg-header: #ffffff;
    --bg-input: #ffffff;
    --bg-message: #f9fafb;
    --bg-message-hover: #f0f2f5;
    --bg-active-nav: #e8f4fd;
    --bg-secondary-btn: #e8ebed;
    --bg-secondary-btn-hover: #d5dce0;
    --bg-scrollbar-track: #f1f1f1;
    --bg-scrollbar-thumb: #c1c1c1;
    --bg-scrollbar-thumb-hover: #a8a8a8;

    --text-primary: #2c3e50;
    --text-secondary: #5a6c7d;
    --text-muted: #95a5a6;
    --text-inverse: #ffffff;

    --border-color: #e1e8ed;
    --shadow-color: rgba(0, 0, 0, 0.05);
    --shadow-heavy: rgba(0, 0, 0, 0.1);

    --color-primary: #1976d2;
    --color-primary-hover: #1565c0;
    --color-danger: #dc3545;
    --color-success: #28a745;
    --color-code: #e83e8c;
    --bg-code: rgba(27, 31, 35, 0.05);
    --bg-pre: #f6f8fa;

    --overlay-color: rgba(0, 0, 0, 0.5);
}

[data-theme="dark"] {
    /* Dark Theme */
    --bg-body: #121212;
    --bg-surface: #1e1e1e;
    --bg-sidebar: #1e1e1e;
    --bg-header: #1e1e1e;
    --bg-input: #2d2d2d;
    --bg-message: #2d2d2d;
    --bg-message-hover: #363636;
    --bg-active-nav: #2c3e50;
    --bg-secondary-btn: #333333;
    --bg-secondary-btn-hover: #444444;
    --bg-scrollbar-track: #1e1e1e;
    --bg-scrollbar-thumb: #555;
    --bg-scrollbar-thumb-hover: #777;

    --text-primary: #e0e0e0;
    --text-secondary: #b0b3b8;
    --text-muted: #888888;
    --text-inverse: #ffffff;

    --border-color: #333333;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --shadow-heavy: rgba(0, 0, 0, 0.7);

    --color-primary: #64b5f6;
    --color-primary-hover: #42a5f5;
    --color-danger: #e57373;
    --color-success: #81c784;
    --color-code: #ff79c6;
    --bg-code: rgba(255, 255, 255, 0.1);
    --bg-pre: #2d2d2d;

    --overlay-color: rgba(0, 0, 0, 0.7);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    /* Smooth transition for theme switching */
    transition: background-color 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background-color: var(--bg-body);
    color: var(--text-primary);
    line-height: 1.6;
}

/* Top Bar */
.top-bar {
    background-color: var(--bg-header);
    border-bottom: 1px solid var(--border-color);
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px var(--shadow-color);
}

.top-bar .container {
    max-width: 100%;
    padding: 0.75rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.user-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-identity {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
}

.btn-login {
    background-color: #4285f4;
    /* Google Blue - Keep consistent */
    color: white;
}

.btn-login:hover {
    background-color: #357ae8;
}

.btn-logout {
    background-color: var(--bg-secondary-btn);
    color: var(--text-secondary);
}

.btn-logout:hover {
    background-color: var(--bg-secondary-btn-hover);
}

/* Layout */
.main-container {
    height: calc(100vh - 60px);
}

.layout {
    display: flex;
    height: 100%;
}

/* Sidebar */
.sidebar {
    width: 220px;
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem 0;
}

.sidebar nav ul {
    list-style: none;
}

.sidebar nav ul li {
    margin-bottom: 0.25rem;
}

.nav-item {
    display: block;
    padding: 0.75rem 1.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: background-color 0.2s ease;
}

.nav-item:hover {
    background-color: var(--bg-body);
    color: var(--text-primary);
}

.nav-item.active {
    background-color: var(--bg-active-nav);
    color: var(--color-primary);
    border-right: 3px solid var(--color-primary);
}

/* Content Area */
.content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Chat Wrapper */
.chat-wrapper {
    display: flex;
    flex-direction: column;
    height: 100%;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

/* Chat Messages Area */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
}

/* Individual Message */
.message {
    margin-bottom: 1rem;
    padding: 0.75rem;
    border-radius: 6px;
    background-color: var(--bg-message);
    transition: background-color 0.2s ease;
}

.message:hover {
    background-color: var(--bg-message-hover);
}

.message-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.message-username {
    font-weight: 600;
    color: var(--color-primary);
    font-size: 0.9rem;
}

.message-time {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.message-content {
    color: var(--text-primary);
    line-height: 1.6;
    word-wrap: break-word;
}

/* Markdown Formatting Styles */
.message-content p {
    margin: 0.5em 0;
}

.message-content p:first-child {
    margin-top: 0;
}

.message-content p:last-child {
    margin-bottom: 0;
}

.message-content strong {
    font-weight: 600;
    color: var(--text-primary);
}

.message-content em {
    font-style: italic;
}

.message-content code {
    background-color: var(--bg-code);
    padding: 0.2em 0.4em;
    border-radius: 3px;
    font-family: 'SFMono-Regular', 'Consolas', 'Liberation Mono', 'Menlo', 'Courier', monospace;
    font-size: 0.85em;
    color: var(--color-code);
}

.message-content pre {
    background-color: var(--bg-pre);
    padding: 1em;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    overflow-x: auto;
    margin: 0.5em 0;
}

.message-content pre code {
    background-color: transparent;
    padding: 0;
    color: var(--text-primary);
    font-size: 0.9em;
}

.message-content a {
    color: var(--color-primary);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s ease;
}

.message-content a:hover {
    border-bottom-color: var(--color-primary);
}

.message-content ul,
.message-content ol {
    margin: 0.5em 0;
    padding-left: 2em;
}

.message-content li {
    margin: 0.25em 0;
}

.message-content blockquote {
    border-left: 4px solid var(--border-color);
    padding-left: 1em;
    margin: 0.5em 0;
    color: var(--text-secondary);
    font-style: italic;
}

.message-content h1,
.message-content h2,
.message-content h3,
.message-content h4,
.message-content h5,
.message-content h6 {
    margin: 0.75em 0 0.5em 0;
    font-weight: 600;
    line-height: 1.3;
}

.message-content h1 {
    font-size: 1.5em;
}

.message-content h2 {
    font-size: 1.3em;
}

.message-content h3 {
    font-size: 1.1em;
}

.message-content h4,
.message-content h5,
.message-content h6 {
    font-size: 1em;
}


/* Message Separator */
.message-separator {
    text-align: center;
    margin: 1.5rem 0;
    position: relative;
}

.message-separator span {
    background-color: var(--bg-surface);
    padding: 0 1rem;
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
    position: relative;
    z-index: 1;
}

.message-separator::before {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    top: 50%;
    height: 1px;
    background-color: var(--border-color);
}

/* Chat Input Wrapper */
.chat-input-wrapper {
    display: flex;
    gap: 0.75rem;
    padding: 1rem 1.5rem;
    background-color: var(--bg-surface);
    border-top: 1px solid var(--border-color);
}

.chat-input-wrapper textarea {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 0.9rem;
    resize: none;
    min-height: 44px;
    max-height: 120px;
    transition: border-color 0.2s ease;
    background-color: var(--bg-input);
    color: var(--text-primary);
}

.chat-input-wrapper textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.chat-input-wrapper textarea:disabled {
    background-color: var(--bg-body);
    color: var(--text-muted);
    cursor: not-allowed;
}

.btn-send {
    background-color: var(--color-primary);
    color: white;
    padding: 0.75rem 1.5rem;
    min-width: 80px;
}

.btn-send:hover:not(:disabled) {
    background-color: var(--color-primary-hover);
}

.btn-send:disabled {
    background-color: var(--bg-secondary-btn);
    color: var(--text-muted);
    cursor: not-allowed;
}

/* Mobile Menu Button (Hidden on Desktop) */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    margin-right: 0.5rem;
    color: var(--text-primary);
    align-items: center;
    justify-content: center;
}

.mobile-menu-btn:hover {
    background-color: var(--bg-body);
    border-radius: 4px;
}

/* Sidebar Overlay */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--overlay-color);
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.sidebar-overlay.active {
    display: block;
    opacity: 1;
}

/* Responsive Styles */
@media (max-width: 768px) {

    /* Header Adjustments */
    .top-bar .container {
        padding: 0.5rem 1rem;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .logo h1 {
        font-size: 1.1rem;
    }

    .user-identity {
        display: none;
        /* Hide name on mobile to save space */
    }

    .btn-login,
    .btn-logout {
        padding: 0.4rem 0.8rem;
        font-size: 0.8rem;
    }

    /* Sidebar - Off-canvas on Mobile */
    .sidebar {
        position: fixed;
        top: 60px;
        /* Below header */
        left: -220px;
        /* Hidden by default */
        bottom: 0;
        z-index: 1001;
        transition: left 0.3s ease;
        box-shadow: 2px 0 5px rgba(0, 0, 0, 0.1);
    }

    .sidebar.active {
        left: 0;
    }

    /* Content Area */
    .content {
        width: 100%;
    }

    .chat-messages {
        padding: 1rem;
    }

    /* Input Area */
    .chat-input-wrapper {
        padding: 0.75rem 1rem;
        position: sticky;
        bottom: 0;
    }

    .chat-input-wrapper textarea {
        font-size: 16px;
        /* Prevent zoom on iOS */
        min-height: 50px;
        /* Larger touch target */
    }
}