:root{color-scheme:light;--bg:#f5f8ff;--text:#172033;--muted:#667085;--glass:rgba(255,255,255,.66);--line:rgba(80,103,140,.18);--changed-color:#fff4b3;--added-color:#cdefd6;--deleted-color:#f7c6c7;--unchanged-color:#e9ecef;--changed-sheet-tab:#b7ddfb;--blue:#007aff;--purple:#7567ff;--cell-w:112px;--cell-h:34px;--row-header-w:54px}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","Segoe UI",sans-serif;color:var(--text);background:radial-gradient(circle at 12% 8%,#b9ddff 0,transparent 32%),radial-gradient(circle at 82% 10%,#e2d4ff 0,transparent 34%),linear-gradient(135deg,#f8fbff,#e9f1ff);min-height:100vh}.top-nav{position:sticky;top:0;z-index:50;display:flex;align-items:center;gap:18px;justify-content:space-between;padding:14px 28px;background:rgba(255,255,255,.72);backdrop-filter:blur(24px);border-bottom:1px solid var(--line)}.brand{display:flex;gap:10px;align-items:center;text-decoration:none;color:var(--text);font-weight:900}.brand-mark{width:40px;height:40px;border-radius:14px;display:grid;place-items:center;color:white;background:linear-gradient(135deg,var(--blue),var(--purple));box-shadow:0 12px 28px rgba(0,122,255,.25)}.nav-links,.language-switcher{display:flex;gap:8px;flex-wrap:wrap}.nav-links a,.language-switcher button,button{border:1px solid var(--line);background:rgba(255,255,255,.72);color:var(--text);padding:10px 14px;border-radius:999px;text-decoration:none;font-weight:800;cursor:pointer}.language-switcher button.active,.primary{background:linear-gradient(135deg,var(--blue),var(--purple));color:#fff;border-color:transparent}.page-shell{width:min(1280px,calc(100% - 32px));margin:auto;padding:28px 0 96px}.glass-card,.panel{background:var(--glass);border:1px solid rgba(255,255,255,.75);box-shadow:0 24px 70px rgba(49,78,130,.16);backdrop-filter:blur(26px);border-radius:30px}.hero{text-align:center;padding:54px 28px;margin-bottom:26px}.eyebrow{display:inline-flex;color:var(--blue);font-weight:900;background:rgba(255,255,255,.62);border:1px solid var(--line);padding:8px 14px;border-radius:999px}.hero h1{font-size:clamp(2.2rem,6vw,5.6rem);line-height:.98;letter-spacing:-.075em;margin:16px auto;max-width:920px}.hero p{max-width:820px;margin:12px auto;color:var(--muted);line-height:1.8}.security-note{display:inline-flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:16px;padding:14px 18px;border-radius:20px;background:#eef8ff;border:1px solid #b8dcff}.app-window{overflow:hidden}.window-bar{display:flex;align-items:center;gap:8px;padding:16px 20px;border-bottom:1px solid var(--line);background:rgba(255,255,255,.52)}.dot{width:13px;height:13px;border-radius:50%}.red{background:#ff5f57}.yellow{background:#ffbd2e}.green{background:#28c840}.window-title{margin-left:10px;color:var(--muted);font-weight:800}.workflow-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:16px;padding:20px}.panel{padding:20px;border-radius:24px;box-shadow:0 14px 36px rgba(49,78,130,.12)}h2,h3,h4{letter-spacing:-.04em;margin-top:0}.upload-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}.upload-card{position:relative;min-height:180px;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:10px;border:1px dashed rgba(0,122,255,.42);border-radius:22px;background:rgba(255,255,255,.6);transition:.2s}.upload-card.dragover,.upload-card:hover{transform:translateY(-2px);box-shadow:0 18px 38px rgba(0,122,255,.14)}.upload-card input{position:absolute;inset:0;opacity:0;cursor:pointer}.upload-card span{width:38px;height:38px;border-radius:14px;display:grid;place-items:center;background:linear-gradient(135deg,var(--blue),var(--purple));color:#fff;font-weight:900}.upload-card em{font-style:normal;color:var(--muted);word-break:break-all}.status{color:var(--muted);font-weight:700}.color-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}.color-grid label,.select-line,.check-line,.freeze-tools label,.modal-grid label{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:10px 12px;background:rgba(255,255,255,.55);border:1px solid var(--line);border-radius:16px}.check-line{justify-content:flex-start}.select-line{margin-top:12px}select,input[type=text],.freeze-tools input{border:1px solid var(--line);border-radius:12px;padding:10px;background:white}.action-row,.download-grid{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}button:disabled{opacity:.45;cursor:not-allowed}.summary-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:12px;padding:0 20px 20px}.summary-grid div{background:rgba(255,255,255,.58);border:1px solid var(--line);border-radius:20px;padding:18px}.summary-grid span{display:block;color:var(--muted);font-weight:800}.summary-grid strong{font-size:2rem}.preview-tools,.download-panel{margin:0 20px 20px}.section-heading{display:flex;justify-content:space-between;gap:16px;align-items:center}.legend{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}.legend-item{display:flex;align-items:center;gap:8px;padding:8px 10px;border-radius:999px;background:white;border:1px solid var(--line)}.legend-swatch{width:28px;height:18px;border-radius:6px;border:1px solid rgba(0,0,0,.08)}.deleted.hatch,.diff-cell.deleted.hatch,.legend-swatch.hatch{background-color:transparent;background-image:repeating-linear-gradient(135deg,rgba(220,53,69,.35) 0,rgba(220,53,69,.35) 6px,transparent 6px,transparent 12px)}.deleted.fill,.diff-cell.deleted.fill,.legend-swatch.fill{background-color:var(--deleted-color)}.deleted.hatch-fill,.diff-cell.deleted.hatch-fill,.legend-swatch.hatch-fill{background-color:var(--deleted-color);background-image:repeating-linear-gradient(135deg,rgba(130,0,0,.28) 0,rgba(130,0,0,.28) 6px,transparent 6px,transparent 12px)}.freeze-tools{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin:12px 0;padding:14px;border-radius:20px;background:rgba(255,255,255,.45);border:1px solid var(--line)}.freeze-tools h4{width:100%;margin:0}.sheet-tabs{display:flex;gap:8px;overflow:auto;margin:12px 0}.sheet-tab{border-radius:14px}.sheet-tab.changed{background:var(--changed-sheet-tab)}.sheet-tab.active{outline:3px solid rgba(0,122,255,.22)}.preview-root{display:grid;grid-template-columns:1fr 1fr;gap:14px}.preview-pane{border:1px solid var(--line);border-radius:18px;background:white;overflow:hidden}.preview-pane h4{margin:0;padding:12px 14px;background:#f8fbff;border-bottom:1px solid var(--line)}.table-scroll{overflow:auto;max-height:520px}.diff-table{border-collapse:separate;border-spacing:0;table-layout:fixed}.diff-table th,.diff-table td{min-width:var(--cell-w);width:var(--cell-w);height:var(--cell-h);max-height:var(--cell-h);padding:7px 9px;border-right:1px solid #e6eaf0;border-bottom:1px solid #e6eaf0;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;background:white}.diff-table th{font-size:.78rem;color:var(--muted);background:#f6f8fb}.diff-table .row-head{min-width:var(--row-header-w);width:var(--row-header-w);text-align:center;position:sticky;left:0;z-index:4;background:#f6f8fb}.diff-cell.changed{background:var(--changed-color)}.diff-cell.added{background:var(--added-color)}.diff-cell.unchanged.painted{background:var(--unchanged-color)}.diff-cell.selected{outline:2px solid var(--blue);outline-offset:-2px}.sticky-cell{position:sticky!important;z-index:5}.sticky-corner{z-index:8!important}.cell-detail{margin-top:14px;padding:16px;border-radius:18px;background:#101828;color:#fff;white-space:pre-wrap;line-height:1.6}.content-section{margin-top:24px;padding:28px}.feature-gallery{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.feature-card{padding:18px;border-radius:24px;background:rgba(255,255,255,.62);border:1px solid var(--line)}.mock-shot{min-height:170px;border-radius:18px;background:#fff;border:1px solid var(--line);padding:12px;overflow:hidden}.mock-table{display:grid;grid-template-columns:repeat(5,1fr);gap:4px}.mock-cell{height:24px;border-radius:6px;background:#eef2f7}.mock-changed{background:var(--changed-color)}.mock-added{background:var(--added-color)}.mock-deleted{background-image:repeating-linear-gradient(135deg,rgba(220,53,69,.35) 0,rgba(220,53,69,.35) 5px,transparent 5px,transparent 10px)}.mock-log{font-family:ui-monospace,Menlo,monospace;font-size:.82rem;line-height:1.7;background:#101828;color:#d1e7ff;border-radius:14px;padding:12px}.faq-list details{background:rgba(255,255,255,.62);border:1px solid var(--line);border-radius:18px;margin:10px 0;padding:14px}.faq-list summary{font-weight:900;cursor:pointer}.history-modal{border:0;background:transparent;width:min(1000px,calc(100% - 24px))}.history-modal::backdrop{background:rgba(16,24,40,.42);backdrop-filter:blur(6px)}.modal-card{background:white;border-radius:26px;padding:0;overflow:hidden;box-shadow:0 30px 90px rgba(0,0,0,.28)}.modal-card header,.modal-card footer{display:flex;justify-content:space-between;align-items:center;padding:18px 22px;background:#f8fbff;border-bottom:1px solid var(--line)}.modal-card footer{border-top:1px solid var(--line);border-bottom:0;justify-content:flex-end}.modal-grid{padding:18px;display:grid;gap:12px}.range-actions{display:flex;gap:10px;flex-wrap:wrap}.mini-preview{max-height:360px;overflow:auto;border:1px solid var(--line);border-radius:18px}.mini-preview table{border-collapse:collapse}.mini-preview td,.mini-preview th{border:1px solid #e6eaf0;padding:6px 8px;min-width:88px;height:30px}.mini-preview .range-selected{background:#dcecff!important;outline:2px solid var(--blue)}@media(max-width:980px){.workflow-grid,.preview-root,.feature-gallery{grid-template-columns:1fr}.summary-grid{grid-template-columns:repeat(2,1fr)}.top-nav{align-items:flex-start;flex-direction:column}.upload-grid{grid-template-columns:1fr}}@media(max-width:640px){.summary-grid,.color-grid{grid-template-columns:1fr}.hero{padding:34px 18px}.page-shell{width:min(100% - 18px,1280px)}}

/* Preview scaling, horizontal sheet tabs, large preview, and reliable sticky panes */
.preview-toolbar{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin:12px 0}.preview-toolbar label{display:flex;align-items:center;gap:10px;padding:10px 12px;background:rgba(255,255,255,.55);border:1px solid var(--line);border-radius:16px}.sheet-tabs{flex-wrap:nowrap;overflow-x:auto;overflow-y:hidden;padding-bottom:8px;align-items:center}.sheet-tab{white-space:nowrap;writing-mode:horizontal-tb;max-width:260px;overflow:hidden;text-overflow:ellipsis}.table-scroll{position:relative}.preview-zoom-surface{display:inline-block;zoom:var(--preview-scale,1)}.diff-table th,.diff-table td{box-sizing:border-box}.diff-table th{background:#f6f8fb}.row-head{background:#f6f8fb!important;text-align:center}.sticky-cell{position:sticky!important}.sticky-column-header{z-index:7!important;background:#f6f8fb!important}.sticky-row-header{z-index:8!important;background:#f6f8fb!important}.sticky-freeze-row{z-index:9!important}.sticky-freeze-col{z-index:10!important}.sticky-corner{z-index:16!important;background:#eef4ff!important}.large-preview-dialog{width:min(96vw,1800px);height:min(94vh,1100px);border:0;background:transparent}.large-preview-dialog::backdrop{background:rgba(16,24,40,.55);backdrop-filter:blur(8px)}.large-preview-card{height:100%;display:flex;flex-direction:column;background:rgba(255,255,255,.94);border-radius:28px;overflow:hidden;box-shadow:0 30px 100px rgba(0,0,0,.28)}.large-preview-card header{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 20px;border-bottom:1px solid var(--line);background:#f8fbff}.large-preview-body{min-height:0;flex:1;display:flex;flex-direction:column;padding:16px}.large-preview-root{min-height:0;flex:1}.large-preview-root .table-scroll{max-height:70vh}.large-preview-root.preview-root{grid-template-columns:1fr 1fr}.large-preview-dialog .cell-detail{max-height:180px;overflow:auto}@media(max-width:900px){.large-preview-root.preview-root{grid-template-columns:1fr}}

/* Refinements for extensible UI, complete data viewing, and clearer feature mockups */
.hero{padding-top:44px}.preview-root{--preview-scale:1}.preview-pane{min-width:0}.table-scroll{max-height:68vh}.preview-zoom-surface{min-width:max-content}.sheet-tabs{gap:10px}.sheet-tab{max-width:none;flex:0 0 auto;overflow:visible;text-overflow:clip;padding-inline:16px}.feature-gallery{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}.feature-card{display:flex;flex-direction:column;gap:12px}.mock-shot{min-height:230px}.mock-table.detailed{grid-template-columns:repeat(6,minmax(32px,1fr));gap:5px}.mock-header,.mock-frozen{background:#dcecff;font-weight:800;color:#175cd3}.mock-caption{display:flex;align-items:center;justify-content:center;gap:8px;margin-bottom:10px;padding:8px;border-radius:12px;background:#eef4ff;color:#175cd3;font-weight:800}.mock-tabs{display:flex;gap:8px;margin-top:10px}.mock-tabs span{padding:6px 10px;border-radius:999px;background:var(--changed-sheet-tab);font-size:.78rem;font-weight:800}.mock-options{display:grid;gap:12px}.mock-options label{padding:10px;border-radius:14px;background:#eef4ff;border:1px solid #c7ddff;font-weight:800}.mock-formula,.mock-style,.freeze-label{padding:12px;border-radius:14px;background:#101828;color:#d1e7ff;font-family:ui-monospace,Menlo,monospace}.mock-style{color:#fecaca}.mock-freeze{display:grid;gap:10px}.large-preview-root .preview-zoom-surface,.preview-root .preview-zoom-surface{will-change:auto}@media(max-width:980px){.table-scroll{max-height:72vh}}

/* Utility tools page */
.utility-page .hero h1{font-size:clamp(2rem,5vw,4.8rem)}.utility-workbench{padding:24px;margin-top:24px}.utility-upload-panel{display:grid;grid-template-columns:1fr minmax(280px,420px);gap:18px;align-items:center;margin-bottom:20px}.utility-file-drop{position:relative;min-height:170px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;text-align:center;border:1px dashed rgba(0,122,255,.42);border-radius:24px;background:rgba(255,255,255,.64)}.utility-file-drop.dragover,.utility-file-drop:hover{box-shadow:0 18px 42px rgba(0,122,255,.14);transform:translateY(-2px)}.utility-file-drop input{position:absolute;inset:0;opacity:0;cursor:pointer}.utility-file-drop span{font-size:2.4rem}.utility-file-drop em{font-style:normal;color:var(--muted)}.utility-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:16px}.utility-card{display:flex;flex-direction:column;gap:10px;min-height:250px;padding:20px;border-radius:24px;background:rgba(255,255,255,.66);border:1px solid var(--line);box-shadow:0 16px 40px rgba(49,78,130,.1)}.utility-card h3{margin:0}.utility-card p{color:var(--muted);line-height:1.7;flex:1}.primary-tool{background:linear-gradient(180deg,rgba(238,248,255,.9),rgba(255,255,255,.72))}.tool-index{width:38px;height:38px;border-radius:14px;display:grid;place-items:center;background:linear-gradient(135deg,var(--blue),var(--purple));color:white;font-weight:900}.utility-guide-list li{margin:10px 0;color:var(--muted);line-height:1.7}@media(max-width:760px){.utility-upload-panel{grid-template-columns:1fr}}

/* SEO, legal, and AdSense readiness content */
.seo-copy-section p,.legal-article p,.legal-article li{color:var(--muted);line-height:1.85}.legal-page{max-width:1040px}.legal-article h1{font-size:clamp(2.1rem,5vw,4rem);letter-spacing:-.06em}.legal-article h2{margin-top:30px}.policy-updated{padding-top:18px;border-top:1px solid var(--line);font-weight:800}.site-footer{display:flex;justify-content:center;gap:12px;flex-wrap:wrap;margin-top:24px;padding:18px}.site-footer a{padding:10px 14px;border-radius:999px;background:rgba(255,255,255,.65);border:1px solid var(--line);text-decoration:none;font-weight:800;color:var(--text)}