:root {
    --bg-color: #f7f7f8;
    --sidebar-bg: #e0e0e0;
    --text-color: #333;
    --accent-color: #000;
    --msg-user-bg: #e0e0e0;
    --msg-bot-bg: #fff;
    --border-color: #ccc;

    /* Dark Mode Defaults (system preference or toggle later) */
    --bg-color-dark: #1e1e1e;
    --sidebar-bg-dark: #252526;
    --text-color-dark: #d4d4d4;
    --accent-color-dark: #007acc;
    --msg-user-bg-dark: #2d2d2d;
    --msg-bot-bg-dark: #1e1e1e;
    --border-color-dark: #3e3e42;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: var(--bg-color-dark);
        --sidebar-bg: var(--sidebar-bg-dark);
        --text-color: var(--text-color-dark);
        --accent-color: var(--accent-color-dark);
        --msg-user-bg: var(--msg-user-bg-dark);
        --msg-bot-bg: var(--msg-bot-bg-dark);
        --border-color: var(--border-color-dark);
    }
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Inter, -apple-system, BlinkMacSystemFont, sans-serif;
    margin: 0;
    display: flex;
    height: 100vh;
    background-color: var(--bg-color);
    color: var(--text-color);
    overflow: hidden;
}

/* Sidebar */
#sidebar {
    width: 260px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 10px;
    transition: transform 0.3s ease;
}

#sidebar.hidden {
    transform: translateX(-100%);
    position: absolute;
    height: 100%;
    z-index: 100;
}

.logo {
    font-size: 1.1rem;
    font-weight: 700;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 10px;
}

.section-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    color: #888;
    margin-top: 20px;
    margin-bottom: 10px;
}

/* Controls */
.control-group {
    margin-bottom: 15px;
}

.control-group label {
    display: block;
    font-size: 0.85rem;
    margin-bottom: 5px;
}

select,
input[type="text"] {
    width: 100%;
    padding: 6px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-color);
}

/* Toggle Switch */
.switch {
    position: relative;
    display: inline-block;
    width: 40px;
    height: 20px;
    vertical-align: middle;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 20px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 14px;
    width: 14px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked+.slider {
    background-color: var(--accent-color);
}

input:checked+.slider:before {
    transform: translateX(20px);
}

/* Main Chat Area */
#main {
    flex: 1;
    display: flex;
    flex-direction: column;
    position: relative;
}

#chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.message {
    max-width: 80%;
    padding: 12px 16px;
    border-radius: 8px;
    line-height: 1.5;
    font-size: 0.95rem;
}

.message.user {
    align-self: flex-end;
    background-color: var(--msg-user-bg);
}

.message.bot {
    align-self: flex-start;
    background-color: var(--msg-bot-bg);
    border: 1px solid var(--border-color);
}

.message.system {
    align-self: center;
    font-size: 0.8rem;
    color: #888;
    background: none;
    border: none;
    padding: 5px;
}

/* Input Area */
#input-area {
    padding: 20px;
    background-color: var(--bg-color);
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 10px;
    align-items: center;
}

textarea {
    flex: 1;
    padding: 10px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background: var(--msg-bot-bg);
    color: var(--text-color);
    resize: none;
    height: 50px;
    font-family: inherit;
}

button {
    padding: 10px 20px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.2s;
}

#send-btn {
    background-color: var(--accent-color);
    color: white;
}

#stop-btn {
    background-color: #d9534f;
    color: white;
    display: none;
    /* Hidden by default */
}

/* KB Action Buttons (Small) */
.kb-action-btn {
    padding: 3px 8px;
    font-size: 0.7rem;
    font-weight: 500;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-color);
    cursor: pointer;
    opacity: 0.7;
    transition: opacity 0.2s, background 0.2s;
}

.kb-action-btn:hover {
    opacity: 1;
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.kb-action-btn.delete:hover {
    background: #d9534f;
    border-color: #d9534f;
}

.secondary-btn {
    padding: 8px;
    background: transparent;
    color: #888;
    border: 1px solid #444;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.secondary-btn:hover {
    background: #333;
    color: #ccc;
    border-color: #666;
}

/* Menu Toggle for Mobile */
#menu-toggle {
    display: none;
    position: absolute;
    top: 10px;
    left: 10px;
    z-index: 200;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-color);
}

@media (max-width: 768px) {
    #sidebar {
        position: absolute;
        height: 100%;
        transform: translateX(-100%);
        z-index: 99;
    }

    #sidebar.active {
        transform: translateX(0);
    }

    #menu-toggle {
        display: block;
    }

    #chat-container {
        padding-top: 50px;
        /* Space for menu toggle */
    }
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: var(--bg-color);
    border-radius: 8px;
    width: 90%;
    max-width: 500px;
    max-height: 80%;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-title {
    font-weight: 600;
    font-size: 1rem;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
    padding: 0;
    line-height: 1;
}

.modal-body {
    padding: 15px 20px;
    overflow-y: auto;
    flex: 1;
}

.kb-manage-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
}

.kb-manage-item:last-child {
    border-bottom: none;
}

.kb-manage-name {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}