/* =============================================================================
 * AENL2SQL Frontend — v2.5 (2026-06-24) Demo-style overhaul
 * Style source: examples/Demo.html + 9 chart demos in examples/
 * Design tokens: warm-white (#f5f4f1) + 8 古风 accent colors
 * Stack: vanilla CSS (no Tailwind), CSS variables, light + dark stub
 * ============================================================================= */

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

:root {
    --bg: #f5f4f1;
    --surface: #ffffff;
    --border: #e5e3de;
    --border-light: #eeedea;
    --text: #1a1916;
    --text-2: #6b6963;
    --text-3: #a8a59e;
    --accent: #2756d6;
    --accent-soft: #eef2ff;
    --sidebar-bg: #fafaf8;
    --sidebar-active: #efeee9;
    --error: #ef4444;
    --error-soft: #fef2f2;
    --success: #22c55e;
    --success-soft: #f0fdf4;
    --wechat: "Times New Roman", "Liberation Serif",
              "Noto Serif CJK SC", "Source Han Serif SC",
              "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", serif;
}

[data-theme="dark"] {
    /* v2.5: dark theme stub — demo only ships light. v2.6 will fill this in. */
    --bg: #1a1916;
    --surface: #2a2926;
    --border: #3a3936;
    --text: #f0ece4;
    --text-2: #b0aea8;
}

html, body { height: 100%; }
body {
    font-family: var(--wechat);
    font-size: 14px;
    font-weight: 400;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ─── App layout (Demo.html .app) ─── */
.app { display: flex; height: 100vh; overflow: hidden; }

/* ─── Sidebar (Demo.html .sidebar) ─── */
.sidebar {
    width: 272px; min-width: 272px;
    display: flex; flex-direction: column;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border);
}
.sidebar-header {
    padding: 20px 20px 16px;
    display: flex; align-items: center; justify-content: space-between;
    border-bottom: 1px solid var(--border-light);
}
.logo { display: flex; align-items: center; gap: 10px; }
.logo-mark {
    width: 20px; height: 20px;
    background: var(--text);
    display: flex; align-items: center; justify-content: center;
    color: var(--sidebar-bg);
    font-size: 9px; font-weight: 700;
    letter-spacing: -0.03em;
}
.logo-text {
    font-size: 16px; font-weight: 600;
    letter-spacing: -0.02em; color: var(--text);
}
.btn-new {
    font-size: 12px; font-weight: 400; color: var(--text-2);
    background: none; border: 1px solid var(--border);
    padding: 5px 12px; cursor: pointer; transition: all 0.15s;
}
.btn-new:hover { border-color: var(--text-2); color: var(--text); }

.conv-list { flex: 1; overflow-y: auto; padding: 8px 0; }
.conv-list::-webkit-scrollbar { width: 0; }
.conv-empty {
    padding: 20px;
    color: var(--text-3);
    font-size: 12px;
    text-align: center;
    letter-spacing: 0.04em;
}
.conv-item {
    position: relative;
    display: flex; align-items: center; gap: 12px;
    padding: 11px 20px 11px 24px;
    cursor: pointer; transition: background 0.12s;
    text-decoration: none; color: inherit;
}
.conv-item:hover { background: var(--border-light); }
.conv-item.active { background: var(--sidebar-active); }
.conv-item.active::before {
    content: '';
    position: absolute; left: 0; top: 10px; bottom: 10px;
    width: 2px; background: var(--accent);
}
.conv-dot {
    width: 6px; height: 6px; border-radius: 50%;
    background: var(--border); flex-shrink: 0;
}
.conv-item.active .conv-dot { background: var(--accent); }
.conv-info { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 3px; }
.conv-title {
    font-size: 14px; font-weight: 400; color: var(--text);
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.conv-time { font-size: 11px; color: var(--text-3); }

.sidebar-footer {
    padding: 14px 20px;
    border-top: 1px solid var(--border-light);
    font-size: 12px; color: var(--text-3);
    display: flex; align-items: center; justify-content: space-between;
    gap: 8px;
}
.sidebar-footer .model-select {
    flex: 1;
    font-size: 11px;
    color: var(--text-2);
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 3px 6px;
    cursor: pointer;
    font-family: inherit;
    max-width: 130px;
}
.status-dot {
    width: 6px; height: 6px; border-radius: 50%;
    background: var(--success); display: inline-block; margin-right: 6px;
}

/* ─── Main / Chat header ─── */
.main { flex: 1; display: flex; flex-direction: column; min-width: 0; }
.chat-header {
    padding: 16px 28px;
    border-bottom: 1px solid var(--border);
    display: flex; align-items: center; justify-content: space-between;
    background: var(--surface); flex-shrink: 0;
}
.chat-header h2 {
    /* [FIXED] 2026-07-08 (per 大帅哥): Cinzel 罗马古典大写衬线,
       配 700 字重 + 1px 字距,让 "AENL2SQL" 有品牌标题感 */
    font-family: 'Cinzel', 'Times New Roman', 'Liberation Serif', serif;
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 1px;
    color: var(--text);
}
.header-actions { display: flex; gap: 4px; }
.header-actions button {
    font-size: 12px; color: var(--text-3);
    background: none; border: 1px solid transparent;
    /* [FIXED] 2026-07-08 (per 大帅哥): 圆角统一 */
    border-radius: 8px;
    padding: 4px 10px; cursor: pointer; transition: all 0.12s;
}
.header-actions button:hover { color: var(--text-2); border-color: var(--border); }

/* ─── Messages (Demo.html .messages — 圆点底纹) ─── */
.messages {
    flex: 1; overflow-y: auto;
    /* [FIXED] 2026-07-10 (per 大帅哥): 智能滚动时,
       scrollTo() 改用 instant,但 CSS 设 smooth 让新消息出现时
       浏览器原生 smooth 滚到新位置。150ms 较短,既"快"又不刺眼。 */
    scroll-behavior: smooth;
    padding: 32px 28px 20px;
    display: flex; flex-direction: column; gap: 24px;
    background-color: var(--bg);
    background-image: radial-gradient(circle, rgba(0,0,0,0.045) 0.7px, transparent 0.7px);
    background-size: 22px 22px;
}
.messages::-webkit-scrollbar { width: 4px; }
.messages::-webkit-scrollbar-track { background: transparent; }
.messages::-webkit-scrollbar-thumb { background: var(--border); }

/* ─── Message bubbles (Demo.html .msg) ─── */
.msg {
    display: flex; flex-direction: column;
    gap: 4px;
    max-width: 640px;
    opacity: 0;
    animation: msgIn 0.35s ease forwards;
}
.msg-user { align-self: flex-end; }
.msg-bot  { align-self: stretch; }
/* [FIXED] 2026-07-10 (per 大帅哥): msg-sender 移到 .msg-header (在气泡上方)。
   header 占满 max-width,Assistant 左对齐,User 右对齐。*/
.msg-header { display: flex; }
.msg-user .msg-header { justify-content: flex-end; }
/* .msg-row 装 (avatar + body) 的 row */
.msg-row {
    display: flex; gap: 12px;
}
.msg-user .msg-row { flex-direction: row-reverse; }
.msg-avatar {
    width: 32px; height: 32px;
    border: 1.5px solid var(--border);
    /* [FIXED] 2026-07-08 (per 大帅哥): 头像圆角 */
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    flex-shrink: 0;
    background: var(--surface);
    color: var(--text-2);
}
.msg-bot .msg-avatar { background: var(--surface); }
.msg-user .msg-avatar {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}
.msg-avatar svg { width: 16px; height: 16px; }
.msg-body {
    display: flex; flex-direction: column;
    gap: 6px; min-width: 0;
}
.msg-user .msg-body { align-items: flex-end; }
.msg-bot .msg-body  { align-items: stretch; }
/* v2.5.2: chart wrapper (not .msg-text!) gets the full bubble width.
 * Important: .msg-body is `align-items: stretch` so children with
 * width:100% actually stretch to the .msg-body width.
 */
.chart-wrapper {
    display: block;
    margin-top: 4px;
    flex: 1 1 auto;
    align-self: stretch;
    min-width: 0;
    box-sizing: border-box;
}
.msg-sender {
    font-size: 12px; font-weight: 500;
    color: var(--text-2); padding: 0 2px;
    letter-spacing: 0.02em;
}
.msg-user .msg-sender { color: var(--accent); }
.msg-text {
    padding: 11px 15px;
    line-height: 1.65; font-size: 14px;
    white-space: pre-wrap; word-break: break-word;
    letter-spacing: 0.01em;
    /* [FIXED] 2026-07-08 (per 大帅哥): 消息气泡圆角 */
    border-radius: 12px;
}
.msg-bot .msg-text {
    background: var(--surface);
    border: 1px solid var(--border);
}
.msg-user .msg-text {
    background: var(--accent-soft);
    border: 1px solid transparent;
}
.msg-time { font-size: 11px; color: var(--text-3); padding: 0 2px; }
.msg-meta {
    font-size: 11px;
    color: var(--text-3);
    padding: 0 2px;
    letter-spacing: 0.02em;
}
/* v2.7.1 (2026-06-25, per 大帅哥): 在消息体里显示 log_id (trace_id 短码)
   方便用户复制后对照 backend log。code 元素给个圆角 + 灰底。 */
.msg-log-id {
    font-size: 11px;
    color: var(--text-2);
    padding: 4px 2px 2px;
    font-family: 'SF Mono', 'Monaco', 'Cascadia Code', monospace;
}
.msg-log-id code {
    background: var(--bg);
    color: var(--text-1);
    padding: 1px 6px;
    border-radius: 6px;
    border: 1px solid var(--border);
    font-size: 11px;
    user-select: all;  /* 一键全选复制 */
}
.msg-error .msg-text {
    border-left: 3px solid var(--error);
    color: #b91c1c;
    background: var(--error-soft);
}
.msg-image {
    max-width: 340px; border: 1px solid var(--border);
    /* [FIXED] 2026-07-08 (per 大帅哥): 图片气泡圆角 */
    border-radius: 12px;
    cursor: zoom-in; overflow: hidden; transition: border-color 0.15s;
}
.msg-image:hover { border-color: var(--text-3); }
.msg-image img { width: 100%; display: block; }
.msg-caption { font-size: 13px; color: var(--text-2); padding: 0 2px; line-height: 1.5; }

/* [FIXED] 2026-07-08 (per 大帅哥): 欢迎语里的"数据范围"区块要够醒目,
   字号大点 + 颜色鲜明 + 卡片式 background,让用户一眼能看到支持哪些数据 */
.data-scope {
    margin-top: 10px;
    padding: 12px 14px;
    background: var(--surface);
    border: 1px solid var(--border-light);
    border-radius: 10px;
}
.scope-item {
    display: flex; gap: 8px;
    padding: 4px 0;
    font-size: 13px;
    color: var(--text);
    line-height: 1.5;
}
.scope-icon { flex-shrink: 0; font-size: 15px; line-height: 1.4; }
.scope-label { font-weight: 600; color: var(--text); margin-right: 4px; }
.scope-desc { color: var(--text-2); font-size: 12px; }
.scope-examples {
    margin-top: 10px; padding-top: 10px;
    border-top: 1px dashed var(--border);
    font-size: 12px; color: var(--text-3);
    line-height: 1.7;
}
.scope-examples b { color: var(--text-2); font-weight: 500; }
.scope-examples i { color: var(--accent); font-style: normal; }
/* [FIXED] 2026-07-09 (per 大帅哥): 数据来源链接 */
.scope-sources {
    margin-top: 8px; padding-top: 8px;
    border-top: 1px dashed var(--border);
    font-size: 11px; color: var(--text-3);
    line-height: 1.7;
}
.scope-sources b { color: var(--text-2); font-weight: 500; }
.scope-sources a {
    color: var(--accent); text-decoration: none;
    border-bottom: 1px dotted var(--accent);
}
.scope-sources a:hover { border-bottom-style: solid; }

/* [FIXED] 2026-07-15 (per 大帅哥): AI 免责声明,
   灰色小字 + ⚠ 图标,放在 welcome 数据来源下面。*/
.scope-disclaimer {
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px dashed var(--border);
    font-size: 11px;
    color: var(--text-3);
    line-height: 1.6;
    letter-spacing: 0.02em;
}

/* [FIXED] 2026-07-09 (per 大帅哥): CSV 下载按钮 (放在表格气泡下) */
.csv-download-btn {
    display: inline-flex; align-items: center; gap: 4px;
    margin-top: 8px; padding: 5px 10px;
    font-size: 12px; color: var(--accent);
    background: var(--accent-soft);
    border: 1px solid var(--accent);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.15s;
}
.csv-download-btn:hover {
    color: #fff; background: var(--accent);
}

/* [FIXED] 2026-07-10 (per 大帅哥): 智能滚动 — "↓ 新消息" 浮动按钮
   用户往上翻历史时,新消息不自动滚,改显示这个按钮在右下角。 */
.newmsg-badge {
    position: fixed;
    right: 24px; bottom: 88px;          /* 输入区上方 */
    padding: 8px 14px;
    font-size: 13px; color: #fff;
    background: var(--accent);
    border: 1px solid var(--accent);
    border-radius: 20px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.18);
    cursor: pointer;
    opacity: 0;
    transform: translateY(8px);
    pointer-events: none;
    transition: opacity 0.2s ease, transform 0.2s ease;
    z-index: 100;
}
.newmsg-badge.show {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}
.newmsg-badge:hover {
    background: var(--text);
    border-color: var(--text);
}

/* ─── Feedback (Demo.html .msg-feedback) ─── */
.msg-feedback {
    display: flex; align-items: center; gap: 2px;
    padding: 2px 0; opacity: 0; transition: opacity 0.2s ease;
}
.msg-bot:hover .msg-feedback,
.msg-feedback.voted { opacity: 1; }
.feedback-btn {
    width: 28px; height: 28px;
    background: none; border: 1px solid transparent;
    /* [FIXED] 2026-07-08 (per 大帅哥): 反馈按钮圆角 */
    border-radius: 8px;
    color: var(--text-3); cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: all 0.15s;
}
.feedback-btn:hover {
    color: var(--text-2);
    border-color: var(--border);
    background: var(--border-light);
}
.feedback-btn.active-up { color: var(--success); border-color: var(--success); background: var(--success-soft); }
.feedback-btn.active-down { color: var(--error); border-color: var(--error); background: var(--error-soft); }
.feedback-btn svg { width: 14px; height: 14px; }

/* ─── Typing indicator (Demo.html .typing-indicator / .typing-dots) ─── */
.typing-indicator .msg-body {
    padding: 12px 18px;
    background: var(--surface);
    border: 1px solid var(--border);
    /* [FIXED] 2026-07-08 (per 大帅哥): 思考中的气泡也圆角,
       跟其他消息气泡视觉一致 */
    border-radius: 12px;
}
.typing-dots { display: flex; gap: 5px; align-items: center; }
.typing-dots span {
    width: 5px; height: 5px; border-radius: 50%;
    background: var(--text-3);
    animation: dotPulse 1.4s ease-in-out infinite;
}
.typing-dots span:nth-child(2) { animation-delay: 0.2s; }
.typing-dots span:nth-child(3) { animation-delay: 0.4s; }

/* ─── Input area (Demo.html .input-area / .input-row) ─── */
.input-area {
    padding: 16px 28px 12px;
    background: var(--surface);
    border-top: 1px solid var(--border); flex-shrink: 0;
}
/* [FIXED] 2026-07-08 (per 大帅哥): 删掉 preview-row (不再支持图片上传),
   删掉 btn-attach,只保留 input + send button */
.input-row { display: flex; gap: 8px; align-items: center; }
.input-wrapper { flex: 1; }
.input-wrapper input {
    width: 100%; height: 40px;
    font-family: var(--wechat); font-size: 14px;
    color: var(--text); background: var(--bg);
    border: 1px solid var(--border);
    /* [FIXED] 2026-07-08 (per 大帅哥): 输入框圆角 */
    border-radius: 10px;
    padding: 0 14px; outline: none;
    transition: border-color 0.15s;
}
.input-wrapper input::placeholder { color: var(--text-3); }
.input-wrapper input:focus { border-color: var(--accent); }
.btn-send {
    width: 40px; height: 40px;
    background: var(--text); border: 1px solid var(--text);
    color: var(--bg); cursor: pointer;
    /* [FIXED] 2026-07-08 (per 大帅哥): 发送按钮圆角 */
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    transition: all 0.15s; flex-shrink: 0;
}
.btn-send:hover { background: var(--accent); border-color: var(--accent); }

/* [FIXED] 2026-07-08 (per 大帅哥): 底部版权栏 */
.app-footer {
    padding: 6px 28px;
    background: var(--surface);
    border-top: 1px solid var(--border-light);
    text-align: center;
    flex-shrink: 0;
}
.footer-text {
    font-size: 11px; color: var(--text-3);
    letter-spacing: 0.3px;
}
.footer-text a {
    color: var(--text-2); text-decoration: none;
    transition: color 0.15s;
}
.footer-text a:hover { color: var(--accent); }

/* [FIXED] 2026-07-10 (per 大帅哥): 吐槽按钮 + 弹窗 */
.btn-feedback {
    margin-left: 10px;
    padding: 3px 10px;
    font-size: 11px;
    color: var(--text-2);
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.15s;
    letter-spacing: 0.3px;
}
.btn-feedback:hover {
    color: var(--accent);
    border-color: var(--accent);
}

.feedback-modal {
    position: fixed; inset: 0;
    display: flex; align-items: center; justify-content: center;
    z-index: 200;
}
.feedback-modal[hidden] { display: none !important; }
.feedback-backdrop {
    position: absolute; inset: 0;
    background: rgba(20, 20, 19, 0.55);
    backdrop-filter: blur(2px);
    cursor: pointer;
}
.feedback-panel {
    position: relative;
    width: 90%; max-width: 480px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 14px;
    box-shadow: 0 12px 36px rgba(0, 0, 0, 0.22);
    padding: 18px 20px 16px;
    animation: panelIn 0.2s ease;
}
@keyframes panelIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}
.feedback-header {
    display: flex; align-items: center; justify-content: space-between;
    margin-bottom: 8px;
}
.feedback-header h3 {
    margin: 0; font-size: 15px; font-weight: 600;
    color: var(--text);
}
.feedback-close {
    background: transparent; border: none;
    color: var(--text-3); font-size: 22px; line-height: 1;
    cursor: pointer; padding: 0 4px;
    transition: color 0.15s;
}
.feedback-close:hover { color: var(--text); }
.feedback-hint {
    margin: 0 0 10px;
    font-size: 12px; color: var(--text-3);
    line-height: 1.5;
}
.feedback-hint code {
    background: var(--bg); padding: 1px 5px; border-radius: 3px;
    font-size: 11px;
}
.feedback-textarea {
    width: 100%;
    padding: 10px 12px;
    font-family: var(--wechat); font-size: 13px;
    color: var(--text);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    resize: vertical;
    outline: none;
    transition: border-color 0.15s;
    box-sizing: border-box;
}
.feedback-textarea:focus { border-color: var(--accent); }
.feedback-textarea::placeholder { color: var(--text-3); }
.feedback-footer {
    display: flex; align-items: center; justify-content: space-between;
    margin-top: 10px;
}
.feedback-counter {
    font-size: 11px; color: var(--text-3);
    letter-spacing: 0.2px;
}
.feedback-actions { display: flex; gap: 8px; }
.feedback-clear,
.feedback-submit {
    padding: 5px 14px;
    font-size: 12px; cursor: pointer;
    border-radius: 6px;
    transition: all 0.15s;
}
.feedback-clear {
    background: transparent; color: var(--text-2);
    border: 1px solid var(--border);
}
.feedback-clear:hover { color: var(--text); border-color: var(--text-2); }
.feedback-submit {
    background: var(--accent); color: #fff;
    border: 1px solid var(--accent);
}
.feedback-submit:hover { background: var(--text); border-color: var(--text); }
.feedback-saved {
    margin-top: 10px; padding: 8px 10px;
    font-size: 12px; color: #15803d;
    background: #f0fdf4; border: 1px solid #bbf7d0;
    border-radius: 6px;
    line-height: 1.5;
}
.feedback-saved.hidden { display: none; }
.feedback-saved code {
    background: #fff; padding: 1px 4px; border-radius: 3px;
    font-size: 11px;
}

/* ─── Lightbox (Demo.html .lightbox — black bg .92 + close button) ─── */
.lightbox {
    position: fixed; inset: 0;
    background: rgba(20, 20, 19, 0.92);
    display: none; align-items: center; justify-content: center;
    z-index: 100; cursor: zoom-out;
}
.lightbox.open { display: flex; }
.lightbox-body { width: 92vw; height: 88vh; }
.lightbox-close {
    position: absolute; top: 20px; right: 24px;
    width: 36px; height: 36px;
    background: none; border: 1px solid rgba(255,255,255,0.2);
    color: rgba(255,255,255,0.7); cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    font-size: 18px; transition: all 0.15s;
    z-index: 101;
}
.lightbox-close:hover { border-color: rgba(255,255,255,0.5); color: #fff; }

/* ─── Date divider (Demo.html .date-divider) ─── */
.date-divider {
    display: flex; align-items: center; gap: 16px; align-self: center;
    opacity: 0; animation: msgIn 0.35s ease forwards;
}
.date-divider::before,
.date-divider::after {
    content: ''; width: 48px; height: 1px; background: var(--border);
}
.date-divider span { font-size: 12px; color: var(--text-3); white-space: nowrap; }

/* ─── Keyframes (Demo.html msgIn / dotPulse) ─── */
@keyframes msgIn {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
}
@keyframes dotPulse {
    0%, 60%, 100% { opacity: 0.25; transform: scale(0.9); }
    30%           { opacity: 1; transform: scale(1.1); }
}

/* ─── Toast (kept from v2.4) ─── */
.toast-container {
    position: fixed; top: 16px; right: 16px;
    display: flex; flex-direction: column; gap: 8px;
    z-index: 200;
}
.toast {
    padding: 10px 14px;
    background: var(--surface); border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 13px; color: var(--text);
    box-shadow: 0 4px 12px rgba(0,0,0,0.06);
    opacity: 0; transform: translateX(20px);
    transition: opacity 0.18s ease, transform 0.18s ease;
}
.toast.show { opacity: 1; transform: translateX(0); }
.toast.toast-error { border-left: 3px solid var(--error); }
.toast.toast-success { border-left: 3px solid var(--success); }
.toast.toast-warn { border-left: 3px solid var(--accent); }

/* ─── Tables inside messages (kept from v2.4) ─── */
.msg-text table {
    width: 100%; border-collapse: collapse; margin-top: 6px;
    font-size: 13px;
}
.msg-text th, .msg-text td {
    padding: 6px 10px; border-bottom: 1px solid var(--border-light);
    text-align: left;
}
.msg-text th { background: var(--sidebar-active); font-weight: 500; }
.msg-text tr:last-child td { border-bottom: none; }

/* ─── Chart container (kept from v2.3 — demo has no chart but we need it) ─── */
.chart {
    width: 100% !important;
    height: 420px;
    min-height: 420px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-top: 6px;
    position: relative;
    display: block;
    /* v2.5: when .chart is wrapped inside a .msg-text bubble (the bot
     * avatar+message layout), the parent's line-height + padding would
     * otherwise compress the chart to a thin vertical strip. Reset. */
    line-height: 0;
    padding: 0;
    box-sizing: border-box;
    /* v2.5.6 (bug 6): ECharts axis name with nameLocation='end' is drawn
     * OUTSIDE the chart grid (in the wrapper padding). Without
     * overflow:visible, the chart canvas clips it. */
    overflow: visible;
}
.chart.bar { height: 460px; }
.chart.scatter { height: 440px; }
.chart.dual-y { height: 460px; }
.chart.correlation { height: 520px; }

/* Fullscreen button (top-right of each chart, hover reveal) */
.fullscreen-btn {
    position: absolute; top: 8px; right: 8px;
    width: 28px; height: 28px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 4px;
    color: var(--text-2);
    cursor: pointer;
    display: none; align-items: center; justify-content: center;
    opacity: 0.85; transition: opacity 0.15s;
    z-index: 5;
}
.chart:hover .fullscreen-btn { display: flex; opacity: 1; }
.fullscreen-btn:hover { color: var(--accent); border-color: var(--accent); }
.fullscreen-btn svg { width: 14px; height: 14px; }

/* ─── Responsive (Demo.html @media) ─── */
@media (max-width: 768px) {
    .sidebar { display: none; }
    .messages { padding: 20px 16px; }
    .input-area { padding: 12px 16px 16px; }
    .chat-header { padding: 14px 16px; }
    .msg { max-width: 88%; }
    .msg-image { max-width: 260px; }
}