:root{color-scheme:light;--bg: #eef6f2;--surface: #ffffff;--surface-soft: #f7fafc;--text: #1d2738;--muted: #647084;--border: #d7e1ee;--primary: #1e63ff;--primary-dark: #174fd1;--green: #19a98e;--shadow: 0 10px 25px rgba(33, 48, 77, .18);--shadow-mini: 0 5px 5px rgba(33, 48, 77, .32)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--text);background:var(--bg);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif}a{color:inherit;text-decoration:none}.site-header{position:sticky;top:0;z-index:10;padding:0 32px;border-bottom:1px solid rgba(215,225,238,.86);background:#fff;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.header-container{width:min(1320px,calc(100% - 28px));margin:0 auto;display:flex;align-items:center;justify-content:space-between;min-height:64px}.brand{display:inline-flex;align-items:center;gap:10px;font-size:20px;font-weight:800}.brand img{display:block;border-radius:9px}.top-nav,.site-footer nav{display:flex;align-items:center;gap:22px;color:var(--muted);font-size:14px;font-weight:650}.top-nav a:hover,.site-footer a:hover{color:var(--primary)}main{width:min(1320px,calc(100% - 32px));margin:0 auto}.home-main{width:min(1320px,calc(100% - 28px));max-width:100%;margin:0 auto;padding-top:10px;box-sizing:border-box}.eyebrow{margin:0 0 8px;color:var(--green);font-size:14px;font-weight:800}h1,h2,p{margin-top:0}h1{margin-bottom:10px;font-size:clamp(36px,7vw,64px);line-height:1.02;letter-spacing:0}.hero p:last-child{max-width:720px;margin-bottom:0;color:var(--muted);font-size:18px;line-height:1.75}.formula-toolbar{position:relative;display:grid;gap:0;max-width:100%;min-width:0;border-radius:0 0 10px 10px;overflow:hidden}.formula-group-tabs{position:absolute;top:0;left:0;right:0;z-index:5;display:flex;flex-wrap:nowrap;gap:8px;max-width:100%;padding-top:6px;overflow-x:auto;overflow-y:hidden;overscroll-behavior-x:contain;-webkit-overflow-scrolling:touch;scrollbar-width:thin}.formula-group-tabs::-webkit-scrollbar{height:4px}.formula-group-tabs::-webkit-scrollbar-thumb{border-radius:999px;background:#64708459}.formula-tab{display:inline-flex;min-width:76px;min-height:40px;flex:0 0 auto;flex-direction:column;align-items:center;justify-content:center;gap:1px;padding:6px 10px 5px;border:1px solid transparent;border-radius:9px 9px 0 0;color:var(--text);background:#e0e0e0;font-size:12px;font-weight:400;box-shadow:var(--shadow-mini)}.formula-tab:hover,.formula-tab.active{border-color:#bfd0e8;color:var(--primary);background:#fff;border-bottom:none}.formula-tab-icon{color:var(--primary);font-family:"Cambria Math","STIX Two Math",Times New Roman,serif;font-size:14px;line-height:1}.formula-block-panel{padding:8px;border-radius:0 10px 10px;background:#fff;border:1px solid #e0e0e0;display:flex;height:164px;align-items:stretch;gap:10px;overflow-x:auto;position:relative;margin-top:50px;box-shadow:var(--shadow)}.formula-block{position:relative;display:flex;flex:0 0 auto;align-items:stretch;height:100%;padding:7px;border:1px solid #e0e0e0;border-radius:8px;background:#e0e0e0}.formula-buttons{display:flex;flex-direction:column;flex-wrap:wrap;flex-shrink:0;gap:5px;box-sizing:border-box;max-height:130px;max-width:175px}.formula-buttons-overflow{max-width:none;max-height:130px}.formula-button{min-width:40px;height:40px;min-height:40px;overflow:hidden;place-items:center;padding:0;border-color:transparent;border-radius:7px;background:#eef2f7;font-family:"Cambria Math","STIX Two Math",Times New Roman,serif;font-size:16px;font-weight:700;line-height:1}.formula-block-more{display:inline-flex;width:8px;min-width:8px;min-height:0;flex:0 0 6px;align-items:center;justify-content:center;margin-left:4px;padding:0;border:none;border-radius:4px;background:transparent;cursor:pointer}.formula-block-more:before{content:"";width:0;height:0;border-top:6px solid transparent;border-bottom:6px solid transparent;border-left:4px solid var(--muted);transition:transform .15s ease}.formula-block-more:hover{background:#ffffff8c}.formula-block-more:hover:before{border-left-color:var(--text)}.formula-block.is-expanded .formula-block-more:before{transform:rotate(90deg);border-left-color:var(--primary)}.formula-block-overflow{position:fixed;z-index:40;display:none;padding:7px;border:1px solid var(--border);border-radius:8px;background:#fff;box-shadow:0 12px 28px #21304d2e}.formula-block.is-expanded .formula-block-overflow{display:block}button{min-height:34px;padding:0 12px;border:1px solid var(--border);border-radius:8px;color:var(--text);background:#fff;font:inherit;font-size:14px;font-weight:700;cursor:pointer}button:hover{border-color:#cacaca;background:#f8fbff}button.active{border-color:var(--primary);color:#fff;background:var(--primary)}.workspace{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);border-radius:12px;overflow:hidden;margin-top:12px;box-shadow:var(--shadow)}.panel{display:flex;min-width:0;flex-direction:column;padding:14px;border:0px solid var(--border);background:#fff}.panel+.panel{border-left:1px solid var(--border)}.workspace.is-visual-mode{grid-template-columns:minmax(0,1fr)}.workspace.is-visual-mode .preview-panel{display:none}.workspace.is-visual-mode .preview-panel.is-export-capture{position:fixed;top:0;left:-10000px;z-index:-1;display:flex;width:640px;flex-direction:column;pointer-events:none}.panel-title{display:flex;min-height:38px;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px}.panel-title h2{margin:0;font-size:19px}.panel-heading,.panel-title-actions,.preview-heading,.preview-title-actions,.zoom-controls{display:inline-flex;min-width:0;align-items:center;gap:5px}.icon-button{display:inline-grid;width:30px;height:30px;place-items:center;padding:0;border:1px solid var(--border);border-radius:8px;color:var(--muted);background:#fff;font-size:16px;font-weight:800;line-height:1;cursor:pointer}.icon-button svg{display:block}.icon-button:hover:not(:disabled){color:var(--text);border-color:#b8c7dd;background:#f8fbff}.icon-button:disabled{opacity:.45;cursor:not-allowed}.zoom-value{min-width:30px;color:var(--muted);font-size:12px;text-align:center}#status{color:var(--green);font-size:13px;font-weight:750}textarea{flex:1;width:100%;min-height:260px;max-height:300px;resize:vertical;padding:18px;border:1px solid var(--border);border-radius:12px;outline:none;color:#152033;background:#fbfdff;font-family:SFMono-Regular,Consolas,Liberation Mono,monospace;font-size:18px;line-height:1.7}textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px #1e63ff24}.toggle-switch{display:inline-flex;padding:3px;border:1px solid var(--border);border-radius:9px;background:#f3f7fb}.toggle-switch button{min-height:29px;padding:0 11px;border:0;border-radius:6px;color:var(--muted);background:transparent;font-size:13px}.toggle-switch button:hover{color:var(--text);background:#e8eef6}.toggle-switch button.active,.toggle-switch button.active:hover{color:#fff;background:var(--primary)}.preview{--preview-zoom: 1;display:grid;min-height:260px;max-height:300px;flex:1;overflow:auto;padding:24px;border:1px solid var(--border);border-radius:12px;background:#fff;place-items:start center;font-size:calc(22px * var(--preview-zoom))}.visual-editor{padding:0}.visual-math-field{min-height:260px;max-height:300px;flex:1;overflow:auto;width:100%;padding:10px;border:1px solid var(--border);border-radius:12px;font-size:24px;box-sizing:border-box;background:#fff}.visual-math-field:focus-within{outline:3px solid rgba(30,99,255,.14)}.visual-math-field::part(container){width:100%}.visual-math-field.is-inline-mode::root .ML__content{width:100%}.visual-math-field.is-inline-mode::part(content){justify-content:flex-start;text-align:left}.visual-math-field.is-block-mode::part(content){justify-content:safe center;text-align:center}.assist-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-top:10px}.assist-upload{display:inline-flex;min-height:34px;align-items:center;justify-content:center;padding:0 12px;border:1px solid var(--border);border-radius:8px;background:#fff;font-size:14px;font-weight:800;cursor:pointer}.assist-upload:hover{border-color:#b8c7dd;background:#f8fbff}.assist-upload input{position:absolute;width:1px;height:1px;opacity:0;pointer-events:none}.assist-row button:disabled{color:#98a2b3;background:#f3f5f8;cursor:not-allowed}#assist-status{color:var(--muted);font-size:13px;font-weight:700}.intro-band{max-width:820px;padding:30px 0 0}.intro-band h2{margin-bottom:8px;font-size:30px;line-height:1.2}.intro-band p:last-child{margin-bottom:0;color:var(--muted);font-size:17px;line-height:1.75}.preview svg{max-width:100%}.export-row{display:flex;gap:8px;margin-top:12px}.edit-export-row{justify-content:flex-end}.edit-image-export{display:none}.workspace.is-visual-mode .edit-image-export{display:block}.edit-panel .action-menu-list{right:0}.preview-export-row{justify-content:flex-start}.action-menu{position:relative}.action-menu summary{display:inline-flex;min-height:34px;align-items:center;justify-content:center;padding:0 12px;border:1px solid var(--border);border-radius:8px;background:#fff;font-size:14px;font-weight:800;cursor:pointer;list-style:none}.action-menu summary::-webkit-details-marker{display:none}.action-menu summary:after{content:"▾";margin-left:8px;color:var(--muted);font-size:12px}.action-menu[open] summary{border-color:var(--primary);color:var(--primary);background:#eef5ff}.action-menu-list{position:absolute;bottom:calc(100% + 6px);z-index:5;display:grid;min-width:108px;gap:4px;padding:6px;border:1px solid var(--border);border-radius:10px;background:#fff;box-shadow:0 12px 30px #21304d24}.action-menu-list button,.menu-action{display:inline-flex;width:100%;align-items:center;justify-content:flex-start;gap:5px;white-space:nowrap;border-color:transparent;text-align:left}.menu-action:before{content:"";flex:0 0 auto;width:15px;height:15px;background-color:var(--muted);mask:var(--menu-action-icon) center / contain no-repeat;-webkit-mask:var(--menu-action-icon) center / contain no-repeat}.menu-action-copy{--menu-action-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='9' y='9' width='13' height='13' rx='2'/%3E%3Cpath d='M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1'/%3E%3C/svg%3E")}.menu-action-download{--menu-action-icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4'/%3E%3Cpolyline points='7 10 12 15 17 10'/%3E%3Cline x1='12' y1='15' x2='12' y2='3'/%3E%3C/svg%3E")}.action-menu-list button:hover,.menu-action:hover{border-color:transparent;background:#dce7f6}.menu-action:hover:before{background-color:var(--text)}.center-toast{position:fixed;top:50%;left:50%;z-index:1000;min-width:160px;max-width:min(420px,calc(100vw - 32px));padding:14px 22px;border-radius:12px;color:#fff;background:#1d2738eb;box-shadow:0 16px 40px #21304d47;font-size:15px;font-weight:700;line-height:1.4;text-align:center;pointer-events:none;opacity:0;transform:translate(-50%,calc(-50% + 8px));transition:opacity .2s ease,transform .2s ease}.center-toast.is-visible{opacity:1;transform:translate(-50%,-50%)}.center-toast.is-error{background:#b12a2af0}.handwrite-modal{position:fixed;top:0;right:0;bottom:0;left:0;z-index:1200;display:grid;place-items:center;padding:20px;background:#121c2d75}.handwrite-modal[hidden]{display:none}.handwrite-dialog{display:grid;width:min(780px,100%);gap:12px;padding:18px 18px 16px;border:1px solid var(--border);border-radius:14px;background:#fff;box-shadow:0 24px 60px #21304d47}.handwrite-header{display:flex;align-items:center;justify-content:space-between;gap:12px}.handwrite-header h3{margin:0;font-size:18px}.handwrite-hint{margin:0;color:var(--muted);font-size:13px;line-height:1.5}.handwrite-canvas-wrap{overflow:hidden;border:1px solid var(--border);border-radius:10px;background:#fff;touch-action:none}#handwrite-canvas{display:block;width:100%;height:auto;cursor:crosshair;touch-action:none;background:#fff}.handwrite-status{min-height:1.2em;margin:0;color:var(--muted);font-size:13px;font-weight:650}.handwrite-status.is-error{color:#d12f2f}.handwrite-actions{display:flex;flex-wrap:wrap;justify-content:flex-end;gap:8px}.handwrite-confirm{border-color:var(--primary);color:#fff;background:var(--primary)}.handwrite-confirm:hover{border-color:var(--primary-dark);background:var(--primary-dark)}.handwrite-confirm:disabled,.handwrite-actions button:disabled{opacity:.55;cursor:not-allowed}.content-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;padding:28px 0 48px}.content-grid article{min-height:180px;padding:22px;border:1px solid var(--border);border-radius:14px;background:#ffffffb8}.content-grid h2{margin-bottom:12px;font-size:20px}.content-grid p{margin-bottom:0;color:var(--muted);line-height:1.75}code{padding:1px 5px;border-radius:5px;background:#eaf0f8;color:#244166;font-family:SFMono-Regular,Consolas,Liberation Mono,monospace}.footer-container{align-items:center;justify-content:space-between;min-height:72px;width:min(1320px,calc(100% - 28px));margin:0 auto;display:flex;padding:0 10px}.page-main{padding:42px 0 56px}.page-hero{display:grid;gap:10px;max-width:1320px;margin-bottom:22px}.page-hero h1{margin-bottom:4px}.page-hero p{margin-bottom:0;color:var(--muted);font-size:18px;line-height:1.75}.legal-main{max-width:1320px}.legal-meta{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px 22px;margin:18px 0 0;padding-top:18px;border-top:1px solid var(--border);color:var(--muted);font-size:14px}.legal-meta div{display:flex;gap:4px}.legal-meta dt{flex:0 0 auto;color:var(--text);font-weight:800}.legal-meta dd{margin:0}.legal-meta a{color:var(--primary);font-weight:750}.doc-shell{display:grid;gap:18px}.doc-card{padding:26px;border:1px solid var(--border);border-radius:16px;background:#ffffffd1;box-shadow:0 12px 30px #21304d12}.doc-card h2{margin-bottom:12px;font-size:22px}.doc-card p,.doc-card li{color:var(--muted);line-height:1.78}.doc-card p{margin-bottom:10px}.doc-card p:last-child,.doc-card ul:last-child,.doc-card ol:last-child{margin-bottom:0}.doc-card a{color:var(--primary);font-weight:700}.doc-card ul,.doc-card ol{margin:0 0 0 20px;padding:0}.code-block{overflow:auto;padding:16px;border:1px solid var(--border);border-radius:12px;background:#101828;color:#dce8ff;font-size:14px;line-height:1.7}@media(max-width:860px){.site-header,.site-footer,.workspace,.content-grid{grid-template-columns:1fr}.site-header,.site-footer{flex-direction:column;align-items:flex-start;justify-content:center;gap:10px;padding:14px 18px}.top-nav,.site-footer nav{flex-wrap:wrap;gap:12px}.panel+.panel{border-top:1px solid var(--border);border-left:0}h1{font-size:38px}.legal-meta{grid-template-columns:1fr}}