/* ===== CSS Variables (Themes) ===== */
:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-sidebar: #0d1117;
    --bg-hover: #1c2333;
    --bg-input: #0d1117;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --border-color: #30363d;
    --accent: #1f6feb;
    --accent-hover: #388bfd;
    --message-user: #1f6feb;
    --message-assistant: #21262d;
    --shadow: 0 8px 24px rgba(0,0,0,0.5);
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f6f8fa;
    --bg-sidebar: #f0f2f5;
    --bg-hover: #e1e4e8;
    --bg-input: #ffffff;
    --text-primary: #1f2328;
    --text-secondary: #656d76;
    --border-color: #d0d7de;
    --accent: #0969da;
    --accent-hover: #0550ae;
    --message-user: #0969da;
    --message-assistant: #f0f2f5;
    --shadow: 0 8px 24px rgba(0,0,0,0.1);
}

/* ===== Reset & Base ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    height: 100vh;
    display: flex;
    overflow: hidden;
}

/* ===== Sidebar ===== */
#sidebar {
    width: 280px;
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    height: 100vh;
}
.sidebar-header {
    padding: 16px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}
.sidebar-header h2 { font-weight: 600; font-size: 1.2rem; color: var(--text-primary); }
.new-chat-btn {
    background: var(--accent);
    color: #fff;
    border: none;
    padding: 6px 12px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.85rem;
    display: flex;
    align-items: center;
    gap: 6px;
}
.new-chat-btn:hover { background: var(--accent-hover); }
.chat-list {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
}
.chat-item {
    padding: 10px 12px;
    border-radius: 8px;
    cursor: pointer;
    margin-bottom: 4px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-secondary);
    transition: background 0.15s;
}
.chat-item:hover { background: var(--bg-hover); color: var(--text-primary); }
.chat-item.active { background: var(--bg-hover); color: var(--text-primary); }
.chat-item .title { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 150px; }
.chat-item .delete-chat {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    visibility: hidden;
}
.chat-item:hover .delete-chat { visibility: visible; }
.chat-item .delete-chat:hover { color: #da3633; }

.sidebar-footer {
    padding: 12px 16px;
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 12px;
}
.icon-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.1rem;
    cursor: pointer;
    padding: 4px;
}
.icon-btn:hover { color: var(--text-primary); }

/* ===== Main Content ===== */
#main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100vh;
    background: var(--bg-primary);
}

/* ===== Status Banner ===== */
#engine-status-banner {
    padding: 8px 20px;
    display: flex;
    align-items: center;
    gap: 16px;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-secondary);
    min-height: 48px;
}
#status-indicator {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}
.status-connected { color: #2ea043; }
.status-disconnected { color: #da3633; }
.status-connecting { color: #ffa500; }

#download-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-left: auto;
}
.download-btn {
    background: var(--accent);
    color: #fff;
    border: none;
    padding: 4px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85rem;
}
.download-btn:hover { background: var(--accent-hover); }
#os-prompt { font-size: 0.85rem; color: var(--text-secondary); }

/* ===== Chat Container ===== */
#chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 20px 40px 8px 40px;
    display: flex;
    flex-direction: column;
}
#messages {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 12px;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}
.message {
    padding: 12px 16px;
    border-radius: 12px;
    max-width: 85%;
    word-wrap: break-word;
    line-height: 1.6;
    font-size: 0.95rem;
}
.message.user {
    align-self: flex-end;
    background: var(--message-user);
    color: #fff;
}
.message.assistant {
    align-self: flex-start;
    background: var(--message-assistant);
    color: var(--text-primary);
}
.message img { max-width: 100%; border-radius: 8px; margin-top: 8px; }

/* ===== Input Area ===== */
#input-area {
    padding: 12px 40px 24px 40px;
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: flex-end;
    gap: 12px;
    background: var(--bg-secondary);
}
#prompt {
    flex: 1;
    padding: 12px 16px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    background: var(--bg-input);
    color: var(--text-primary);
    font-size: 0.95rem;
    resize: none;
    outline: none;
    font-family: inherit;
    min-height: 48px;
    max-height: 120px;
}
#prompt:focus { border-color: var(--accent); }
.send-btn, .image-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.3rem;
    cursor: pointer;
    padding: 8px 12px;
    border-radius: 8px;
    transition: background 0.2s;
}
.send-btn:hover, .image-btn:hover { background: var(--bg-hover); color: var(--text-primary); }
.send-btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ===== Auth Overlay ===== */
#auth-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    backdrop-filter: blur(4px);
}
.auth-modal {
    background: var(--bg-secondary);
    padding: 40px;
    border-radius: 16px;
    width: 360px;
    max-width: 90%;
    box-shadow: 0 16px 48px rgba(0,0,0,0.6);
}
.auth-modal h2 { margin-bottom: 8px; color: var(--text-primary); }
.auth-modal p { color: var(--text-secondary); margin-bottom: 20px; font-size: 0.95rem; }
.auth-modal input {
    width: 100%;
    padding: 12px;
    margin-bottom: 12px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--bg-input);
    color: var(--text-primary);
    font-size: 0.95rem;
}
.auth-modal input:focus { border-color: var(--accent); outline: none; }
.auth-modal button {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: var(--accent);
    color: #fff;
    font-size: 1rem;
    cursor: pointer;
}
.auth-modal button:hover { background: var(--accent-hover); }
.auth-error { color: #da3633; margin-bottom: 12px; font-size: 0.9rem; }
#auth-toggle-text { margin-top: 16px; text-align: center; color: var(--text-secondary); font-size: 0.9rem; }
#auth-toggle-text a { color: var(--accent); cursor: pointer; text-decoration: none; }

/* ===== Modals ===== */
.modal {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    backdrop-filter: blur(4px);
}
.modal-content {
    background: var(--bg-secondary);
    padding: 32px;
    border-radius: 16px;
    width: 480px;
    max-width: 90%;
    max-height: 80vh;
    overflow-y: auto;
}
.close-btn {
    float: right;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
}
.close-btn:hover { color: var(--text-primary); }
.setting-item {
    margin-bottom: 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.setting-item label { font-weight: 500; }
.setting-item button {
    background: var(--bg-hover);
    border: 1px solid var(--border-color);
    padding: 6px 14px;
    border-radius: 6px;
    cursor: pointer;
    color: var(--text-primary);
}
.setting-item button:hover { background: var(--border-color); }
#bug-report {
    width: 100%;
    height: 80px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--bg-input);
    color: var(--text-primary);
    padding: 8px;
    font-family: inherit;
    margin-bottom: 12px;
}
#submit-bug {
    background: var(--accent);
    color: #fff;
    border: none;
    padding: 8px 20px;
    border-radius: 6px;
    cursor: pointer;
}
#submit-bug:hover { background: var(--accent-hover); }

/* ===== Responsive ===== */
@media (max-width: 640px) {
    #sidebar { width: 0; display: none; }
    #main-content { width: 100%; }
    #chat-container { padding: 12px 16px; }
    #input-area { padding: 8px 16px; }
}