:root[data-theme=cobalt]{--bg: #f6f8fc;--surface: #ffffff;--surface-2: #f1f5fb;--hair: #e3e9f2;--text: #16233c;--muted: #61708a;--faint: #8695ab;--accent: #1e40af;--accent-soft: #e8edfb;--accent-ink: #1e3a8a;--amber: #b45309;--amber-bg: #fef3e2;--good: #157347;--crit: #b42318;--good-bg: #e6f4ec;--crit-bg: #fdeceb;--shadow: 0 1px 2px #1e293b0f, 0 8px 24px -12px #1e293b1f;--radius: 14px;--radius-sm: 9px;--bubble-user: #1e40af;--bubble-user-text: #fff;--glow: none;--hero: linear-gradient(150deg,#1e40af,#3b82f6);--font-num: ui-sans-serif, system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;--code-bg: #1e293b;--code-text: #e2e8f0}:root[data-theme=graphite]{--bg: #0f141c;--surface: #161d28;--surface-2: #1b2431;--hair: #26313f;--text: #e5edf7;--muted: #8ea0b6;--faint: #647588;--accent: #5b9dff;--accent-soft: #14243d;--accent-ink: #bcd6ff;--amber: #fbbf24;--amber-bg: #3a2f14;--good: #34d399;--crit: #f87171;--good-bg: #10281f;--crit-bg: #341a1c;--shadow: 0 1px 0 #ffffff08 inset, 0 12px 32px -16px #000c;--radius: 14px;--radius-sm: 9px;--bubble-user: #22406e;--bubble-user-text: #eaf2ff;--glow: 0 0 24px -6px #5b9dff55;--hero: linear-gradient(150deg,#0f141c,#1e3357);--font-num: ui-monospace, "SF Mono", "Cascadia Code", Menlo, monospace;--code-bg: #0b1017;--code-text: #e5edf7}body{margin:0;background:var(--bg);color:var(--text);font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif}.chat-layout{display:flex;height:100vh}.sidebar{width:260px;background:var(--surface);border-right:1px solid var(--hair);flex-shrink:0;overflow-y:auto;display:flex;flex-direction:column}.sidebar.collapsed{width:0;overflow:hidden;border-right:none}.sidebar-header{padding:12px 16px;border-bottom:1px solid var(--hair)}.sidebar-list{flex:1;overflow-y:auto}.sidebar-date-group{padding:4px 16px;font-size:12px;color:var(--faint);margin-top:8px}.sidebar-item{padding:8px 16px;cursor:pointer;border-radius:6px;margin:2px 8px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:14px;display:flex;align-items:center;justify-content:space-between}.sidebar-item:hover{background:var(--surface-2)}.sidebar-item.active{background:var(--accent-soft);color:var(--accent-ink)}.sidebar-item .delete-btn{opacity:0;transition:opacity .2s;flex-shrink:0}.sidebar-item:hover .delete-btn{opacity:1}.sidebar-footer{padding:12px 16px;border-top:1px solid var(--hair);display:flex;align-items:center;justify-content:space-between}.chat-main{flex:1;display:flex;flex-direction:column;min-width:0;background:var(--bg)}.chat-header{height:48px;border-bottom:1px solid var(--hair);display:flex;align-items:center;padding:0 16px;font-weight:600;gap:12px}.message-list{flex:1;overflow-y:auto;padding:16px}.message-list-empty{display:flex;align-items:center;justify-content:center;height:100%;color:var(--muted);font-size:15px}.message{margin-bottom:16px;max-width:800px;margin-left:auto;margin-right:auto}.message-user{text-align:right}.message-user .message-content{background:var(--bubble-user);color:var(--bubble-user-text);display:inline-block;padding:8px 16px;border-radius:16px;max-width:70%;text-align:left;word-break:break-word;line-height:1.6;box-shadow:var(--shadow)}.message-assistant .message-content{background:var(--surface-2);display:inline-block;padding:12px 16px;border-radius:16px;max-width:85%;text-align:left;word-break:break-word;line-height:1.6;box-shadow:var(--shadow)}.message-assistant .message-content p{margin:0 0 8px}.message-assistant .message-content p:last-child{margin-bottom:0}.message-assistant .message-content table{border-collapse:collapse;width:100%;margin:8px 0}.message-assistant .message-content th,.message-assistant .message-content td{border:1px solid var(--hair);padding:6px 10px;text-align:left;font-size:13px}.message-assistant .message-content th{background:var(--surface-2);font-weight:600}.message-assistant .message-content pre{background:var(--code-bg);color:var(--code-text);padding:12px;border-radius:8px;overflow-x:auto;font-size:13px}.message-assistant .message-content code{background:var(--surface-2);padding:1px 4px;border-radius:3px;font-size:13px}.message-assistant .message-content pre code{background:none;padding:0}.message-assistant .message-content ul,.message-assistant .message-content ol{padding-left:20px;margin:4px 0}.msg-actions{display:flex;gap:4px;margin-top:6px;opacity:0;transition:opacity .2s}.message-assistant:hover .msg-actions{opacity:1}.msg-action-btn{display:inline-flex;align-items:center;gap:4px;padding:2px 6px;border:none;background:none;color:var(--faint);cursor:pointer;font-size:13px;border-radius:4px;transition:all .15s}.msg-action-btn:hover{color:var(--text);background:var(--surface-2)}.msg-action-btn.copied{color:var(--good)}.msg-action-label{font-size:12px}.chat-input-area{border-top:1px solid var(--hair);background:var(--surface);padding:12px 16px;max-width:800px;margin:0 auto;width:100%;box-sizing:border-box}.chat-input-wrapper{display:flex;gap:8px}.typing-indicator{display:inline-flex;gap:4px;padding:4px 0}.typing-dot{width:6px;height:6px;background:var(--faint);border-radius:50%;animation:pulse 1.5s infinite}.typing-dot:nth-child(2){animation-delay:.3s}.typing-dot:nth-child(3){animation-delay:.6s}@keyframes pulse{0%,to{opacity:.3}50%{opacity:1}}.download-link{display:inline-flex;align-items:center;gap:4px;color:var(--accent);text-decoration:none;padding:4px 8px;background:var(--accent-soft);border-radius:4px;margin-top:4px}.download-link:hover{background:color-mix(in srgb,var(--accent) 20%,var(--accent-soft))}.example-questions{max-width:680px;margin:0 auto;padding:60px 16px 40px}.welcome-section{text-align:center;margin-bottom:32px}.welcome-icon{font-size:48px;margin-bottom:12px;line-height:1}.welcome-title{font-size:22px;font-weight:600;color:var(--text);margin:0 0 8px}.welcome-subtitle{font-size:14px;color:var(--muted);margin:0;line-height:1.6}.category-tabs{display:flex;gap:10px;justify-content:center;margin-bottom:20px;flex-wrap:wrap}.category-tab{padding:8px 20px;border-radius:20px;border:1px solid var(--hair);background:var(--surface);cursor:pointer;font-size:14px;color:var(--muted);transition:all .2s;display:flex;align-items:center;gap:6px}.category-tab:hover{border-color:var(--accent);color:var(--accent);transform:translateY(-1px);box-shadow:0 2px 6px color-mix(in srgb,var(--accent) 12%,transparent)}.category-tab.active{background:var(--bubble-user);color:var(--bubble-user-text);border-color:var(--bubble-user);box-shadow:0 2px 8px color-mix(in srgb,var(--accent) 25%,transparent)}.category-icon{font-size:16px}.question-list{display:flex;flex-direction:column;gap:10px}.question-card{padding:14px 20px;border:1px solid var(--hair);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow);cursor:pointer;font-size:15px;color:var(--text);transition:all .2s;display:flex;align-items:center;justify-content:space-between}.question-card:hover{border-color:var(--accent);background:var(--accent-soft);transform:translate(4px)}.question-card:hover .question-arrow{color:var(--accent);transform:translate(3px)}.question-text{flex:1}.question-arrow{color:var(--faint);font-size:16px;transition:all .2s;margin-left:12px;flex-shrink:0}.skeleton-tab{width:80px;height:36px;background:linear-gradient(90deg,var(--surface-2) 25%,var(--hair) 50%,var(--surface-2) 75%);background-size:200% 100%;animation:skeleton-shimmer 1.5s infinite}.skeleton-card{height:52px;background:linear-gradient(90deg,var(--surface-2) 25%,var(--hair) 50%,var(--surface-2) 75%);background-size:200% 100%;animation:skeleton-shimmer 1.5s infinite}@keyframes skeleton-shimmer{0%{background-position:200% 0}to{background-position:-200% 0}}@media(max-width:768px){.sidebar{position:absolute;z-index:100;height:100%;background:var(--surface)}.sidebar.collapsed{display:none}.message-user .message-content{max-width:85%}.message-assistant .message-content{max-width:95%}}