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var(--space-2);border:0;border-radius:var(--radius-control);background:transparent;color:var(--color-on-surface);font-family:inherit;font-size:19px;font-weight:800;letter-spacing:-.03em;line-height:1;white-space:nowrap;cursor:pointer;transform:none;filter:none;-webkit-tap-highlight-color:transparent}._logo_1huax_64 svg{flex:none;width:30px;height:19px;fill:none;stroke:var(--color-primary);stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}._logo_1huax_64:hover:not(:disabled){background:var(--color-surface-hover);filter:none}._logo_1huax_64:active:not(:disabled){transform:none;background:var(--color-surface-active)}._logo_1huax_64:focus-visible{outline:3px solid var(--color-focus-ring);outline-offset:0}._sheetBar_1huax_9{display:flex;flex:none;align-items:center;height:calc(var(--bar-row) + env(safe-area-inset-top,0px));padding:env(safe-area-inset-top,0px) var(--space-3) 0 max(var(--bar-inline),env(safe-area-inset-left,0px));border:0}._sheetBar_1huax_9 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h2{margin:0;font-size:32px}.native-family p{margin:0}.native-family .eyebrow{margin-bottom:12px}.native-family-actions{display:flex;flex-wrap:wrap;gap:12px}.native-family-actions button{min-height:48px}@media(max-width:360px){.native-family{padding:18px;gap:16px}.native-family-actions{display:grid}}.amp-checkbox-row{display:grid;grid-template-columns:auto minmax(0,1fr);align-items:center;gap:var(--space-3);width:100%;min-height:var(--target-size);padding:var(--space-3);border:1px solid var(--color-border-strong);border-radius:var(--radius-control);background:var(--color-surface-raised);color:var(--color-on-surface);font:inherit;text-align:left;cursor:pointer}.amp-checkbox-row:hover:not(:has(input:disabled)){filter:none;background:var(--color-surface-sunken)}.amp-checkbox-row:has(input:checked){border-color:var(--color-primary);background:var(--color-secondary)}.amp-checkbox-row:has(input:focus-visible){outline:3px solid 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#553a6b;--color-avatar-2: #f1e2d8;--color-on-avatar-2: #6f3f20;--color-avatar-3: #e3ead6;--color-on-avatar-3: #44541f;--color-avatar-4: #d9ebe8;--color-on-avatar-4: #1d5450;--color-avatar-5: #f0dfe4;--color-on-avatar-5: #6e3446;--color-avatar-6: #eee6d2;--color-on-avatar-6: #5c4a1b;--color-avatar-7: #dfe8df;--color-on-avatar-7: #2f5238;--color-provider: #ffffff;--color-on-provider: #1f1f1f;--color-provider-border: #747775;--color-brand-google-red: #ea4335;--color-brand-google-blue: #4285f4;--color-brand-google-yellow: #fbbc05;--color-brand-google-green: #34a853;--color-brand-microsoft-red: #f25022;--color-brand-microsoft-green: #7fba00;--color-brand-microsoft-blue: #00a4ef;--color-brand-microsoft-yellow: #ffb900}@media screen and (prefers-color-scheme:dark){:root:not([data-theme=light]){color-scheme:dark;--color-surface: #122522;--color-on-surface: #e9f0e8;--color-surface-raised: #122522;--color-on-surface-raised: #e9f0e8;--color-surface-sunken: #233c36;--color-on-surface-sunken: #e9f0e8;--color-answer: #122522;--color-on-answer: #e9f0e8;--color-answer-border: #6f8c80;--color-menu: #223a34;--color-on-menu: #eef5ed;--color-primary: #8bd1b5;--color-on-primary: #102320;--color-secondary: #244638;--color-on-secondary: #dcf1e6;--color-selected: #8bd1b5;--color-on-selected: #102320;--color-success: #1f4630;--color-on-success: #d3f2dd;--color-success-accent: #91d6ac;--color-danger: #4f3028;--color-on-danger: #ffdccc;--color-danger-accent: #ffb18d;--color-warning: #47391a;--color-on-warning: #f8e3b4;--color-warning-accent: #e8b85c;--color-info: #1f3a4f;--color-on-info: #d3e7f6;--color-info-accent: #8cc1e6;--color-muted-text: #b6c9bd;--color-subtle-text: #a8bcb0;--color-border: #365148;--color-border-strong: #6f8c80;--color-focus-ring: #a4e0c7;--color-scrim: #000000a6;--color-shadow: #00000059;--color-figure-paper: #1a302c;--color-figure-ink: #dcebe3;--color-figure-grid: #3a564d;--color-figure-axis: #8eab9e;--color-figure-accent: #6fc7b4;--color-figure-accent-fill: #24493f;--color-figure-warm: #f0a17c;--color-figure-warm-fill: #5a3526;--color-figure-gold: #e8b85c;--color-figure-gold-fill: #4d3d1c;--color-figure-gold-fill-strong: #5e4a22;--color-figure-accent-fill-strong: #2f5d51;--color-figure-empty: #223a34;--color-strand-number: #86ade3;--color-strand-operations: #ac9fe3;--color-strand-fractions: #eb9e68;--color-strand-decimals: #dbb94f;--color-strand-ratio: #e590ab;--color-strand-algebra: #8bd1b5;--color-strand-functions: #72c3e3;--color-strand-geometry: #83cdac;--color-strand-measurement: #abcb6e;--color-strand-data: #70cccc;--color-strand-probability: #c7a0e3;--color-strand-modeling: #ee9a75;--color-rail: #0e1f1c;--color-on-rail: #e9f0e8;--color-course-band: #8bd1b521;--color-meter: #6db59a;--color-avatar-0: #25384c;--color-on-avatar-0: #cfe0f2;--color-avatar-1: #382d48;--color-on-avatar-1: #e2d3f0;--color-avatar-2: #47322a;--color-on-avatar-2: #f3d6c4;--color-avatar-3: #37402a;--color-on-avatar-3: #dbe8bf;--color-avatar-4: #1f3f3d;--color-on-avatar-4: #c6ece6;--color-avatar-5: #452c36;--color-on-avatar-5: #f2cfdb;--color-avatar-6: #40381f;--color-on-avatar-6: #eee0b4;--color-avatar-7: #2a3f30;--color-on-avatar-7: #cfe8d6;--color-provider: #131314;--color-on-provider: #e3e3e3;--color-provider-border: #8e918f;--color-brand-google-red: #ea4335;--color-brand-google-blue: #4285f4;--color-brand-google-yellow: #fbbc05;--color-brand-google-green: #34a853;--color-brand-microsoft-red: #f25022;--color-brand-microsoft-green: #7fba00;--color-brand-microsoft-blue: #00a4ef;--color-brand-microsoft-yellow: #ffb900}}:root[data-theme=dark]{color-scheme:dark;--color-surface: #122522;--color-on-surface: #e9f0e8;--color-surface-raised: #122522;--color-on-surface-raised: #e9f0e8;--color-surface-sunken: #233c36;--color-on-surface-sunken: #e9f0e8;--color-answer: #122522;--color-on-answer: #e9f0e8;--color-answer-border: #6f8c80;--color-menu: #223a34;--color-on-menu: #eef5ed;--color-primary: #8bd1b5;--color-on-primary: #102320;--color-secondary: #244638;--color-on-secondary: #dcf1e6;--color-selected: #8bd1b5;--color-on-selected: #102320;--color-success: #1f4630;--color-on-success: #d3f2dd;--color-success-accent: #91d6ac;--color-danger: #4f3028;--color-on-danger: #ffdccc;--color-danger-accent: #ffb18d;--color-warning: #47391a;--color-on-warning: #f8e3b4;--color-warning-accent: #e8b85c;--color-info: #1f3a4f;--color-on-info: #d3e7f6;--color-info-accent: #8cc1e6;--color-muted-text: #b6c9bd;--color-subtle-text: #a8bcb0;--color-border: #365148;--color-border-strong: #6f8c80;--color-focus-ring: #a4e0c7;--color-scrim: #000000a6;--color-shadow: #00000059;--color-figure-paper: #1a302c;--color-figure-ink: #dcebe3;--color-figure-grid: #3a564d;--color-figure-axis: #8eab9e;--color-figure-accent: #6fc7b4;--color-figure-accent-fill: #24493f;--color-figure-warm: #f0a17c;--color-figure-warm-fill: #5a3526;--color-figure-gold: #e8b85c;--color-figure-gold-fill: #4d3d1c;--color-figure-gold-fill-strong: #5e4a22;--color-figure-accent-fill-strong: #2f5d51;--color-figure-empty: #223a34;--color-strand-number: #86ade3;--color-strand-operations: #ac9fe3;--color-strand-fractions: #eb9e68;--color-strand-decimals: #dbb94f;--color-strand-ratio: #e590ab;--color-strand-algebra: #8bd1b5;--color-strand-functions: #72c3e3;--color-strand-geometry: #83cdac;--color-strand-measurement: #abcb6e;--color-strand-data: #70cccc;--color-strand-probability: #c7a0e3;--color-strand-modeling: #ee9a75;--color-rail: #0e1f1c;--color-on-rail: #e9f0e8;--color-course-band: #8bd1b521;--color-meter: #6db59a;--color-avatar-0: #25384c;--color-on-avatar-0: #cfe0f2;--color-avatar-1: #382d48;--color-on-avatar-1: #e2d3f0;--color-avatar-2: #47322a;--color-on-avatar-2: #f3d6c4;--color-avatar-3: #37402a;--color-on-avatar-3: #dbe8bf;--color-avatar-4: #1f3f3d;--color-on-avatar-4: #c6ece6;--color-avatar-5: #452c36;--color-on-avatar-5: #f2cfdb;--color-avatar-6: #40381f;--color-on-avatar-6: #eee0b4;--color-avatar-7: #2a3f30;--color-on-avatar-7: #cfe8d6;--color-provider: #131314;--color-on-provider: #e3e3e3;--color-provider-border: #8e918f;--color-brand-google-red: #ea4335;--color-brand-google-blue: #4285f4;--color-brand-google-yellow: #fbbc05;--color-brand-google-green: #34a853;--color-brand-microsoft-red: #f25022;--color-brand-microsoft-green: #7fba00;--color-brand-microsoft-blue: #00a4ef;--color-brand-microsoft-yellow: #ffb900}:root{--state-hover: 8%;--state-active: 14%;--color-surface-hover: color-mix( in srgb, var(--color-on-surface) var(--state-hover), var(--color-surface) );--color-surface-active: color-mix( in srgb, var(--color-on-surface) var(--state-active), var(--color-surface) );--color-selected-tint: color-mix( in srgb, var(--color-primary) 9%, var(--color-surface) );--color-surface-raised-hover: color-mix( in srgb, var(--color-on-surface-raised) var(--state-hover), var(--color-surface-raised) );--color-surface-raised-active: color-mix( in srgb, var(--color-on-surface-raised) var(--state-active), var(--color-surface-raised) );--color-menu-hover: color-mix( in srgb, var(--color-on-menu) var(--state-hover), var(--color-menu) );--color-menu-active: color-mix( in srgb, var(--color-on-menu) var(--state-active), var(--color-menu) );--color-primary-hover: color-mix( in srgb, var(--color-on-primary) var(--state-hover), var(--color-primary) );--color-primary-active: color-mix( in srgb, var(--color-on-primary) var(--state-active), var(--color-primary) );--color-secondary-hover: color-mix( in srgb, var(--color-on-secondary) var(--state-hover), var(--color-secondary) );--color-secondary-active: color-mix( in srgb, var(--color-on-secondary) var(--state-active), var(--color-secondary) );--color-selected-hover: color-mix( in srgb, var(--color-on-selected) var(--state-hover), var(--color-selected) );--color-rail-hover: color-mix( in srgb, var(--color-on-rail) var(--state-hover), var(--color-rail) );--color-disabled: color-mix( in srgb, var(--color-on-surface) 10%, var(--color-surface) );--color-on-disabled: color-mix( in srgb, var(--color-on-surface) 62%, var(--color-surface) );--space: 16px;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Inter,system-ui,sans-serif;color:var(--color-on-surface);background:var(--color-surface)}:root{--space-1: 4px;--space-2: 8px;--space-3: 12px;--space-4: 16px;--space-5: 24px;--space-6: 32px;--wave-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='12' viewBox='0 0 24 12'%3E%3Cpath d='M0 6C4 .67 8 .67 12 6S20 11.33 24 6' fill='none' stroke='%23000' stroke-width='1.8'/%3E%3C/svg%3E");--wave-edge: linear-gradient( 90deg, transparent, #000 14%, #000 86%, transparent );--scroll-edge: linear-gradient(90deg, #000 calc(100% - 28px) , transparent);--radius-control: 12px;--radius-panel: 20px;--target-size: 48px;--motion-fast: .15s;--motion-step: .9s;--motion-trace: 1.3s;--motion-hold: 1.4s;--ease-standard: cubic-bezier(.22, .7, .18, 1);--text-body: 17px;--text-label: 14px;--text-small: 13px;--text-price: 22px;--width-form: 480px;--text-title-min: 28px;--text-title-max: 42px;--shadow-overlay: 0 20px 80px var(--color-shadow);--font-display: "Iowan Old Style", "Palatino Linotype", Georgia, serif;--text-heading-1: 34px;--text-heading-2: 22px;--text-heading-3: 17px;--text-heading-4: 15px;--text-dense: 15px;--text-table: 14px;--text-table-small: 12.5px;--text-figure: 22px;--numeric: tabular-nums lining-nums;--space-7: 48px;--space-8: 64px;--radius-small: 8px;--width-rail: 232px;--width-content-wide: 1120px;--width-sheet: 500px;--field-height: 48px;--field-radius: var(--radius-control);--field-padding-inline: var(--space-4);--field-surface: var(--color-surface);--field-on: var(--color-on-surface);--field-border: var(--color-answer-border);--field-placeholder: var(--color-subtle-text)}:root{--color-print-paper: #ffffff;--color-print-ink: #000000;--color-print-rule: #aaaaaa}@media(prefers-reduced-motion:reduce){:root{--motion-fast: 0ms;--motion-step: 0ms;--motion-trace: 0ms;--motion-hold: 0ms}}:root{--atlas-surface: #071019;--atlas-on-surface: #edf4fa;--atlas-panel: #101d2b;--atlas-on-panel: #edf4fa;--atlas-muted: #a4b6c9;--atlas-border: #2a3d50;--atlas-accent: #a4efdd;--atlas-on-accent: #08231e;--atlas-area-0: #62a9ff;--atlas-area-1: #ac8bfa;--atlas-area-2: #55e3ed;--atlas-area-3: #f1c779;--atlas-area-4: #73ddba;--atlas-area-5: #ee94bb;--atlas-light: #ffffff;--atlas-transparent: #ffffff00;--atlas-halo-core: #ffffffd9;--atlas-halo-edge: #ffffff38;--atlas-vignette: #123747;--atlas-prerequisite: #5bd7ed;--atlas-dependent: #d0a5ff}:root{--atlas-scene-surface: var(--atlas-surface);--atlas-scene-on-surface: var(--atlas-on-surface);--atlas-scene-panel: var(--atlas-panel);--atlas-scene-on-panel: var(--atlas-on-panel);--atlas-scene-muted: var(--atlas-muted);--atlas-scene-border: var(--atlas-border);--atlas-scene-accent: var(--atlas-accent);--atlas-scene-on-accent: var(--atlas-on-accent);--atlas-scene-area-0: var(--atlas-area-0);--atlas-scene-area-1: var(--atlas-area-1);--atlas-scene-area-2: var(--atlas-area-2);--atlas-scene-area-3: var(--atlas-area-3);--atlas-scene-area-4: var(--atlas-area-4);--atlas-scene-area-5: var(--atlas-area-5)}.glossary-term{position:relative;z-index:1;display:inline;margin:0;padding:0;border:0;border-radius:4px;background:transparent;color:inherit;font:inherit;line-height:inherit;letter-spacing:inherit;text-align:inherit;text-decoration:underline dotted;text-decoration-color:var(--color-primary);text-decoration-thickness:2px;text-underline-offset:.24em;max-inline-size:100%;white-space:normal;cursor:pointer;transition:background var(--motion-fast) ease}.glossary-term:after{content:"";position:absolute;left:50%;top:50%;width:max(100%,44px);height:44px;transform:translate(-50%,-50%)}.glossary-term:hover:not(:disabled){filter:none;background:var(--color-secondary);color:var(--color-on-secondary);text-decoration-style:solid}.glossary-term:active:not(:disabled){transform:none}.glossary-term:focus-visible{outline:2px solid var(--color-focus-ring);outline-offset:2px}.glossary-term-end{white-space:nowrap}.glossary-term-mark{position:relative;top:-.55em;display:inline-flex;align-items:center;justify-content:center;width:1.25em;height:1.25em;margin:0 -.1em 0 .12em;border-radius:50%;background:var(--color-secondary);color:var(--color-on-secondary);font-size:.62em;font-style:normal;font-weight:750;line-height:1;vertical-align:baseline;text-decoration:none}.key-words h3{margin:0 0 var(--space-2)}.key-words ul,.term-card-list{display:flex;flex-wrap:wrap;gap:var(--space-2);margin:0;padding:0;list-style:none}.problem-lesson .key-words li,.term-card-list li{margin:0}.key-word{position:relative;z-index:1;display:inline-flex;align-items:center;gap:var(--space-1);min-height:44px;margin:0;padding:0 var(--space-4);border:1px solid var(--color-border);border-radius:999px;background:var(--color-secondary);color:var(--color-on-secondary);font:inherit;font-size:15px;font-weight:600;line-height:1.2;white-space:nowrap;cursor:pointer}.key-word:hover:not(:disabled){filter:none;background:var(--color-secondary-hover)}.key-word:active:not(:disabled){transform:none;background:var(--color-secondary-active)}.key-word:focus-visible{outline:2px solid var(--color-focus-ring);outline-offset:2px}.key-word-more,.key-word-more:hover:not(:disabled){border-color:var(--color-border-strong);background:transparent;color:var(--color-on-surface)}.term-card-list{margin-top:var(--space-3)}.key-word .glossary-term-mark{top:0;margin:0;background:var(--color-surface-raised);color:var(--color-on-surface-raised);font-size:.72em}.term-dialog{position:fixed;inset:0;width:100%;height:100%;max-width:none;max-height:none;margin:0;padding:0;border:0;overflow:hidden;background:transparent;color:var(--color-on-surface-raised)}.term-dialog::backdrop{background:var(--color-scrim)}.term-card{position:absolute;right:0;bottom:0;left:0;display:flex;flex-direction:column;max-height:min(85dvh,640px);padding:0 var(--space-5) calc(var(--space-5) + env(safe-area-inset-bottom));overflow-y:auto;overscroll-behavior:contain;border-radius:var(--radius-panel) var(--radius-panel) 0 0;background:var(--color-surface-raised);color:var(--color-on-surface-raised);box-shadow:var(--shadow-overlay)}.term-card-grab{display:flex;flex:none;align-items:center;justify-content:center;height:44px;margin:0 calc(-1 * var(--space-5));cursor:grab;touch-action:none}.term-card-grab span{width:40px;height:5px;border-radius:3px;background:var(--color-border-strong)}.term-card-header{display:flex;flex:none;align-items:flex-start;gap:var(--space-2)}.term-card-titles{flex:1;min-width:0;padding-top:var(--space-2)}.term-card-trail{margin:0 0 2px;color:var(--color-muted-text);font-size:var(--text-small);line-height:1.3}.term-card-header h2{margin:0;font-size:22px;font-weight:700;line-height:1.25;letter-spacing:-.01em;overflow-wrap:break-word}.term-card-header h2:focus{outline:none}.term-card-back,.term-card-close{display:inline-flex;flex:none;align-items:center;justify-content:center;width:44px;height:44px;margin:0;padding:0;border:0;border-radius:50%;background:var(--color-surface-sunken);color:var(--color-on-surface-sunken)}.term-card-back:hover:not(:disabled),.term-card-close:hover:not(:disabled){filter:none;background:var(--color-surface-raised-active)}.term-card-back:focus-visible,.term-card-close:focus-visible{outline:2px solid 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