:root{--bg-color: #141416;--header-bg: #141416;--card-bg: #1c1c20;--card-border: #2c2c34;--inner-bg: #161619;--input-bg: #141416;--input-border: #33333c;--text-primary: #e6e6ea;--text-secondary: #9e9ea6;--text-muted: #6e6e76;--accent-pill: #282830;--accent-pill-hover: #32323d;--btn-bg: #26262e;--btn-hover: #30303a;--btn-active-bg: #383844;--solve-btn-bg: #2d2d36;--solve-btn-hover: #3a3a46;--border-color: #28282f;--font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;--math-font: "Latin Modern Math", "Computer Modern", "STIX Two Math", "Times New Roman", serif;--mono-font: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;--max-width: 860px;--highlight-red: #ff4d4d;--highlight-green: #00e676;--blue-link: #5c9cff;--active-blue-bg: 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.topic-modal-card{transform:scale(.95)}.topic-modal-header{display:flex;align-items:center;justify-content:space-between}.topic-modal-title{font-size:17px;font-weight:700;color:var(--text-primary)}.topic-modal-close{background:transparent;border:none;color:var(--text-muted);font-size:22px;cursor:pointer;line-height:1}.topic-modal-close:hover{color:var(--text-primary)}.topic-modal-desc{font-size:13px;color:var(--text-secondary);line-height:1.5}.topic-example-box{background-color:var(--inner-bg);border:1px solid var(--border-color);border-radius:6px;padding:12px 14px;display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap}.topic-example-label{font-size:12px;color:var(--text-muted)}.topic-example-code{font-family:var(--mono-font);font-size:13px;color:#79c0ff;background:#ffffff0d;padding:2px 6px;border-radius:4px}.topic-load-btn{background-color:var(--btn-bg);border:1px solid var(--border-color);color:var(--text-primary);font-size:12px;font-weight:600;padding:6px 12px;border-radius:4px;cursor:pointer;transition:background .15s ease}.topic-load-btn:hover{background-color:var(--active-blue-bg);border-color:var(--blue-link)}.mathdf-inner-rule-card{width:100%;max-width:480px;margin:14px auto;background-color:#151518;border:1px solid #2e2e38;border-radius:8px;padding:16px 22px;display:flex;flex-direction:column;align-items:center;position:relative;box-shadow:inset 0 1px 3px #0006}.mathdf-inner-rule-card .rule-title-line{align-self:flex-start;font-size:13px;font-weight:500;color:#b0b0ba;margin-bottom:10px}.mathdf-inner-rule-card .rule-math-box{font-size:16px;color:#fff;margin:8px 0}.mathdf-inner-rule-card .rule-where-line{font-size:12px;color:#787884;margin-top:6px}.mathdf-inner-rule-card .rule-n-line{font-size:13px;font-weight:600;color:#e0e0ea;font-family:var(--mono-font);margin-bottom:12px}.mathdf-inner-rule-card .rule-eval-box{font-size:18px;color:#fff;margin:10px 0}.mathdf-inner-rule-card .rule-bottom-vars{font-size:13px;font-style:italic;color:#5c9cff;letter-spacing:2px;margin-top:12px}@media (max-width: 680px){.header-container{flex-direction:column;height:auto;padding:10px 16px;gap:10px}.topic-grid{grid-template-columns:1fr;gap:8px}.topic-nav-header{flex-direction:column;gap:4px}.calc-toolbar{flex-direction:column;align-items:stretch}.solve-variable-panel{justify-content:flex-end}.functions-list{grid-template-columns:1fr}.floating-sidebar{display:none}.graph-container{flex-direction:column}.graph-control-panel{width:100%}.footer-container{flex-direction:column;align-items:center;text-align:center;gap:10px}}