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

:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #111118;
    --bg-tertiary: #1a1a25;
    --bg-hover: #222230;
    --text-primary: #e8e8ed;
    --text-secondary: #9d9dae;
    --text-muted: #5c5c6e;
    --accent: #6366f1;
    --accent-hover: #5558e6;
    --accent-light: #a5b4fc;
    --accent-glow: rgba(99,102,241,0.25);
    --border: #222233;
    --user-bubble: linear-gradient(135deg, #6366f1, #8b5cf6);
    --ai-bubble: #1a1a25;
    --danger: #ef4444;
    --success: #22c55e;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    line-height: 1.5;
}

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

/* Sidebar */
.sidebar {
    width: 280px;
    background: var(--bg-secondary);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border);
    flex-shrink: 0;
    transition: transform 0.3s cubic-bezier(0.4,0,0.2,1);
}

.sidebar.hidden { transform: translateX(-280px); width: 0; overflow: hidden; min-width: 0; }

.sidebar-header { padding: 20px 16px 12px; }

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.logo-icon {
    width: 34px; height: 34px;
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    box-shadow: 0 4px 12px var(--accent-glow);
}

.new-chat-btn {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    transition: all 0.2s;
}

.new-chat-btn:hover { background: var(--bg-hover); border-color: var(--accent); }

.chat-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px 10px;
}

.chat-list-item {
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 3px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.15s;
}

.chat-list-item:hover { background: var(--bg-hover); }
.chat-list-item.active { background: var(--bg-hover); color: var(--text-primary); }

.chat-list-item .delete-chat {
    opacity: 0;
    background: none; border: none;
    color: var(--text-muted); cursor: pointer; font-size: 15px;
    padding: 2px 6px; border-radius: 4px;
}

.chat-list-item:hover .delete-chat { opacity: 1; }
.chat-list-item .delete-chat:hover { color: var(--danger); }

.sidebar-footer {
    padding: 12px 16px 16px;
    border-top: 1px solid var(--border);
}

.settings-btn {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 12px;
    margin-bottom: 12px;
    transition: all 0.2s;
}

.settings-btn:hover { background: var(--bg-hover); color: var(--text-primary); }

.contact-info { font-size: 11px; color: var(--text-muted); }
.contact-line { margin-bottom: 2px; }

/* Main */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    position: relative;
}

.topbar {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    border-bottom: 1px solid var(--border);
    gap: 12px;
    background: var(--bg-primary);
}

.menu-toggle {
    background: none; border: none;
    color: var(--text-secondary); font-size: 20px;
    cursor: pointer; padding: 4px;
    display: none;
    border-radius: 6px;
}

.menu-toggle:hover { color: var(--text-primary); background: var(--bg-hover); }

.topbar-title {
    font-weight: 600; font-size: 15px;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.topbar-right { margin-left: auto; }

.model-badge {
    padding: 4px 12px;
    background: var(--accent-glow);
    color: var(--accent-light);
    border-radius: 20px;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.3px;
    border: 1px solid rgba(99,102,241,0.3);
}

/* Chat Area */
.chat-area {
    flex: 1;
    overflow-y: auto;
    scroll-behavior: smooth;
}

/* Welcome Screen */
.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    padding: 40px;
    text-align: center;
    position: relative;
}

.welcome-screen.hidden { display: none; }

.welcome-glow {
    position: absolute;
    width: 300px; height: 300px;
    background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
}

.welcome-logo {
    width: 72px; height: 72px;
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    border-radius: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    margin-bottom: 20px;
    box-shadow: 0 8px 32px var(--accent-glow);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.welcome-screen h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 6px;
    background: linear-gradient(135deg, var(--text-primary), var(--accent-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-sub { color: var(--text-secondary); font-size: 14px; margin-bottom: 32px; }

/* Feature Cards */
.feature-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    max-width: 540px;
    width: 100%;
}

.feature-card {
    padding: 20px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    cursor: pointer;
    text-align: center;
    transition: all 0.2s;
}

.feature-card:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 16px var(--accent-glow);
}

.feature-icon { font-size: 28px; margin-bottom: 10px; }
.feature-name { font-size: 14px; font-weight: 600; color: var(--text-primary); margin-bottom: 4px; }
.feature-desc { font-size: 12px; color: var(--text-muted); }

/* Messages */
.messages {
    max-width: 800px;
    margin: 0 auto;
    padding: 24px 20px;
}

.message {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.message.user { flex-direction: row-reverse; }

.message-avatar {
    width: 34px; height: 34px;
    border-radius: 8px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 13px;
}

.message.user .message-avatar {
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    color: #fff;
}

.message.assistant .message-avatar {
    background: var(--bg-tertiary);
    color: var(--accent-light);
    border: 1px solid var(--border);
}

.message-content {
    max-width: 80%;
    line-height: 1.75;
    font-size: 14px;
}

.message.user .message-content {
    background: var(--user-bubble);
    padding: 12px 18px;
    border-radius: var(--radius-lg) var(--radius-lg) 6px var(--radius-lg);
    color: #fff;
}

.message.assistant .message-content {
    padding: 4px 0;
}

.message-content p { margin-bottom: 10px; }
.message-content p:last-child { margin-bottom: 0; }

.message-content pre {
    background: #0d1117;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px 18px;
    overflow-x: auto;
    margin: 10px 0;
    font-size: 13px;
}

.message-content code {
    font-family: "JetBrains Mono", "Fira Code", "SF Mono", monospace;
    font-size: 13px;
}

.message-content pre code { background: none; padding: 0; font-size: 13px; }

.message-content :not(pre) > code {
    background: var(--bg-tertiary);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 12.5px;
    color: var(--accent-light);
}

.message-content ul, .message-content ol { padding-left: 22px; margin: 10px 0; }
.message-content li { margin-bottom: 6px; }

.message-content table {
    border-collapse: collapse;
    width: 100%;
    margin: 10px 0;
    font-size: 13px;
}

.message-content th, .message-content td {
    border: 1px solid var(--border);
    padding: 10px 14px;
    text-align: left;
}

.message-content th { background: var(--bg-tertiary); font-weight: 600; }

.message-content blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 14px;
    margin: 10px 0;
    color: var(--text-secondary);
    font-style: italic;
}

/* Typing */
.typing-indicator {
    display: flex;
    gap: 5px;
    padding: 12px 0 4px;
}

.typing-indicator span {
    width: 7px; height: 7px;
    background: var(--accent-light);
    border-radius: 50%;
    animation: bounce 1.5s infinite ease-in-out both;
}

.typing-indicator span:nth-child(1) { animation-delay: -0.32s; }
.typing-indicator span:nth-child(2) { animation-delay: -0.16s; }

@keyframes bounce {
    0%, 80%, 100% { transform: scale(0.5); opacity: 0.5; }
    40% { transform: scale(1); opacity: 1; }
}

/* Input Area */
.input-area {
    padding: 12px 20px 16px;
    border-top: 1px solid var(--border);
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    background: var(--bg-primary);
}

.input-box {
    display: flex;
    align-items: flex-end;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 8px 8px 8px 16px;
    gap: 8px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-box:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.input-box textarea {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 14px;
    resize: none;
    outline: none;
    line-height: 1.6;
    max-height: 160px;
    font-family: inherit;
    padding: 4px 0;
}

.input-box textarea::placeholder { color: var(--text-muted); }

.send-btn {
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    color: #fff;
    border: none;
    width: 38px; height: 38px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all 0.2s;
    box-shadow: 0 2px 8px var(--accent-glow);
}

.send-btn:hover { transform: scale(1.05); box-shadow: 0 4px 16px var(--accent-glow); }
.send-btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none; box-shadow: none; }

.input-hint {
    text-align: center;
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 10px;
}

/* Modal */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.7);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

.modal-overlay.show { display: flex; }

.modal {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 28px;
    width: 90%;
    max-width: 420px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.5);
    animation: modalIn 0.25s ease;
}

@keyframes modalIn {
    from { opacity: 0; transform: scale(0.95) translateY(10px); }
    to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal h2 { margin-bottom: 6px; font-size: 18px; font-weight: 700; }

.modal-desc { color: var(--text-secondary); font-size: 13px; margin-bottom: 22px; }

.form-group { margin-bottom: 18px; }

.form-group label {
    display: block;
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 6px;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 11px 14px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    outline: none;
    transition: border-color 0.2s;
}

.form-group input:focus { border-color: var(--accent); }

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 22px;
}

.btn-primary, .btn-secondary {
    padding: 9px 22px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    border: none;
    transition: all 0.2s;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    color: #fff;
    box-shadow: 0 2px 8px var(--accent-glow);
}

.btn-primary:hover { box-shadow: 0 4px 16px var(--accent-glow); transform: translateY(-1px); }

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

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

/* Error */
.error-message {
    color: var(--danger);
    padding: 10px 14px;
    background: rgba(239,68,68,0.08);
    border: 1px solid rgba(239,68,68,0.2);
    border-radius: var(--radius-sm);
    font-size: 13px;
    margin: 8px 0;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

/* Scrollbar */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: #444; }

/* Input Tools */
.input-tools {
    display: flex;
    gap: 4px;
    align-items: center;
}

.tool-btn {
    background: none;
    border: 1px solid transparent;
    color: var(--text-muted);
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s;
}

.tool-btn:hover { color: var(--text-primary); background: var(--bg-hover); }
.tool-btn.active { color: var(--accent); border-color: rgba(99,102,241,0.3); }

.input-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

/* Image Preview */
.preview-area {
    position: relative;
    display: flex;
    align-items: flex-start;
    margin-bottom: 8px;
    animation: fadeIn 0.2s ease;
}

.preview-area img {
    max-height: 120px;
    max-width: 200px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    object-fit: cover;
}

.clear-preview {
    position: absolute;
    top: -8px;
    right: -8px;
    width: 22px; height: 22px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
}

.clear-preview:hover { color: var(--danger); border-color: var(--danger); }

/* Generated Image */
.generated-image {
    max-width: 100%;
    max-height: 400px;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: transform 0.2s;
    border: 1px solid var(--border);
}

.generated-image:hover { transform: scale(1.02); }

.image-prompt {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 6px;
    font-style: italic;
}

/* Uploaded image in user message */
.user-image-msg {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.uploaded-thumb {
    max-width: 200px;
    max-height: 200px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    object-fit: cover;
    border: 1px solid var(--border);
}

.image-question {
    font-size: 13px;
    color: rgba(255,255,255,0.85);
}

/* Image Modal */
.image-modal-content {
    position: relative;
    max-width: 90vw;
    max-height: 90vh;
    animation: modalIn 0.25s ease;
}

.image-modal-content img {
    max-width: 90vw;
    max-height: 85vh;
    border-radius: var(--radius-md);
    object-fit: contain;
    border: 1px solid var(--border);
}

.close-btn {
    position: absolute;
    top: -40px;
    right: 0;
    background: var(--bg-tertiary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    width: 36px; height: 36px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 22px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.close-btn:hover { background: var(--bg-hover); border-color: var(--danger); color: var(--danger); }

/* Mobile */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0; top: 0; bottom: 0;
        z-index: 100;
        box-shadow: 4px 0 20px rgba(0,0,0,0.3);
    }
    .sidebar.hidden { transform: translateX(-100%); width: 280px; min-width: 0; }
    .menu-toggle { display: flex; }
    .messages { padding: 16px 12px; }
    .message-content { max-width: 88%; }
    .feature-cards { grid-template-columns: 1fr; }
    .input-area { padding: 10px 12px 14px; }
    .topbar { padding: 10px 14px; }
    .generated-image { max-height: 280px; }
}