@font-face{font-family:Inter;src:url(/fonts/Inter-Regular.woff2) format("woff2");font-weight:400;font-display:swap}@font-face{font-family:Inter;src:url(/fonts/Inter-SemiBold.woff2) format("woff2");font-weight:600;font-display:swap}@font-face{font-family:Inter;src:url(/fonts/Inter-Bold.woff2) format("woff2");font-weight:700;font-display:swap}@font-face{font-family:Inter;src:url(/fonts/Inter-ExtraBold.woff2) format("woff2");font-weight:800;font-display:swap}:root{--ink: #171717;--muted: #5f5f5c;--line: #d9d9d6;--soft: #faf9f6;--accent: #df4b18;--pin: #d8232a;--green: #2d7250;--shell: min(1320px, calc(100% - 64px) )}*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{margin:0;background:#fff;color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-size:16px;line-height:1.5}a{color:inherit;text-decoration:none}a:focus-visible,button:focus-visible{outline:3px solid var(--accent);outline-offset:2px}img,svg{max-width:100%}.shell{width:var(--shell);margin-inline:auto}.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);clip-path:inset(50%);white-space:nowrap}.site-header{border-bottom:1px solid #e8e8e5}.header-row{height:84px;display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:40px}.header-row .site-nav{justify-self:center}.brand{display:flex;align-items:center;gap:11px;font-size:27px;font-weight:800;letter-spacing:-1px}.brand-mark{width:38px;height:38px;border:2px solid var(--ink);position:relative;flex:none;background:repeating-linear-gradient(90deg,transparent 0 6px,var(--ink) 6px 7px),repeating-linear-gradient(0deg,transparent 0 8px,var(--ink) 8px 9px)}.brand-mark:after{content:"";width:8px;height:8px;border-radius:50%;background:var(--ink);position:absolute;left:12px;top:9px;box-shadow:12px 9px 0 var(--ink)}.site-nav{display:flex;gap:28px;font-size:15px;white-space:nowrap}.site-nav a{padding:4px 0}.site-nav a:hover{color:var(--accent)}.header-cta{justify-self:end;border:1px solid var(--ink);border-radius:7px;padding:12px 20px;font-weight:600}main{padding-top:40px}.crumbs{color:#6c6c69;font-size:14px;margin-bottom:24px}.crumbs span{padding:0 8px}h1{font-size:clamp(32px,5vw,50px);line-height:1.04;letter-spacing:-2px;margin:0 0 12px}.lead{font-size:18px;color:#3c3c3a;max-width:780px;margin:0 0 30px}.section{padding:54px 0;border-bottom:1px solid #ecece8}.section:last-of-type{border-bottom:0}.section-title{font-size:clamp(24px,3vw,32px);letter-spacing:-1px;margin:0 0 10px}.section-lead{color:var(--muted);margin:0 0 26px;max-width:760px}.chord-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.chord-card{border:1px solid var(--line);border-radius:9px;padding:14px 10px 16px;display:flex;flex-direction:column;align-items:center;gap:6px;background:#fff}.chord-card .diagram{width:100%;max-width:210px;height:auto}.chord-card .chord-name{font-size:27px;font-weight:800;line-height:1}.chord-card .chord-name a{display:block}.chord-card a:hover .chord-name,.chord-card .chord-name a:hover{color:var(--accent)}.artifact-bar{margin:24px 0 40px;border:1px solid #bbb;border-radius:9px;padding:20px 22px 16px;display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.artifact-bar .note{grid-column:1 / -1;text-align:center;font-size:14px;color:var(--muted)}.btn{display:flex;align-items:center;justify-content:center;gap:9px;min-height:56px;border:1px solid var(--ink);border-radius:7px;background:#fff;color:var(--ink);font:700 16px/1 inherit;cursor:pointer;padding:0 14px;text-align:center}.btn:hover{background:var(--soft)}.btn--primary{background:var(--ink);color:#fff}.btn--primary:hover{background:#000}.btn--pin{border-color:var(--pin);color:var(--pin)}.btn--pin:hover{background:#fff5f5}.btn svg{width:19px;height:19px;flex:none}.feature{display:grid;grid-template-columns:minmax(0,460px) 1fr;gap:56px;align-items:start;padding-bottom:46px}.print-preview{display:block;width:100%;max-width:420px;height:auto;background:#fff;border:1px solid #ccc;box-shadow:0 4px 14px #00000021}.intro{border-left:1px solid #d8d8d5;padding-left:48px}.intro p{font-size:17px;color:#333;max-width:620px}.step{display:grid;grid-template-columns:34px 1fr;gap:14px;margin:22px 0}.step .num{width:30px;height:30px;border-radius:50%;background:#111;color:#fff;display:grid;place-items:center;font-weight:800;font-size:14px}.step strong{display:block;font-size:17px;margin-bottom:4px}.step span{color:#444}.quick-links{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}.quick-links a{border:1px solid var(--accent);color:var(--accent);border-radius:7px;padding:12px 16px;font-weight:600;font-size:15px}.quick-links a:hover{background:#fdf1ec}.card-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.link-card{border:1px solid var(--line);border-radius:8px;padding:20px;display:grid;grid-template-columns:1fr;gap:6px;align-content:start}.link-card--with-diagram{grid-template-columns:96px 1fr;column-gap:18px}.link-card--with-diagram .diagram{grid-row:1 / span 3;width:96px;height:auto;align-self:start}.link-card:hover{border-color:#9a9a96}.link-card b{font-size:17px}.link-card span{color:var(--muted);font-size:15px}.link-card em{color:var(--accent);font-style:normal;font-weight:700;margin-top:8px}.tabs{display:grid;grid-template-columns:repeat(4,1fr);border:1px solid var(--line);border-radius:9px 9px 0 0;overflow:hidden;background:var(--soft)}.tab{border:0;border-right:1px solid var(--line);background:transparent;padding:16px 12px;text-align:left;font:700 15px/1.2 inherit;color:#454542;cursor:pointer}.tab:last-child{border-right:0}.tab span{display:block;color:#777;font-size:12px;font-weight:600;margin-top:4px}.tab[aria-selected=true]{background:#fff;box-shadow:inset 0 -4px var(--accent);color:#111}.variant-stage{border:1px solid var(--line);border-top:0;border-radius:0 0 9px 9px;background:#fff}.variant-panel{display:none;grid-template-columns:55% 45%}.variant-panel[data-active]{display:grid}.diagram-side{padding:32px 44px 26px;display:grid;grid-template-columns:minmax(0,330px) 1fr;align-items:center;gap:40px}.hero-diagram{width:100%;max-width:330px}.variant-copy .eyebrow{font-size:13px;font-weight:800;text-transform:uppercase;letter-spacing:.08em;color:var(--accent)}.variant-copy h2{font-size:29px;line-height:1.12;margin:10px 0;letter-spacing:-.7px}.variant-copy p{color:#444;margin:0 0 18px}.fact{border-top:1px solid #e6e6e2;padding:12px 0;display:flex;justify-content:space-between;gap:16px;font-size:15px}.fact b{font-weight:800;text-align:right}.variant-actions{grid-column:1 / -1;display:grid;grid-template-columns:repeat(4,1fr);gap:10px;border-top:1px solid #e7e7e3;padding-top:20px}.variant-actions .btn{min-height:48px;font-size:14px}.artifact-side{background:var(--soft);border-left:1px solid var(--line);padding:26px 34px 32px;display:flex;flex-direction:column;align-items:center}.artifact-head{width:100%;display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:16px}.artifact-head strong{font-size:17px}.artifact-head .size{font-size:12px;border:1px solid #bbb;border-radius:20px;padding:6px 10px;color:#555;white-space:nowrap}.print-card{display:block;width:100%;max-width:286px;height:auto;background:#fff;border:1px solid #cfcfcb;box-shadow:0 5px 16px #00000021}.artifact-note{font-size:13px;color:var(--muted);margin-top:12px;text-align:center}.compare-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.shape-card{border:1px solid var(--line);border-radius:9px;padding:18px 16px 14px;display:flex;flex-direction:column;gap:4px}.shape-card .badge{align-self:flex-start;border-radius:20px;background:#f1f0eb;padding:6px 9px;font-size:11px;font-weight:800;color:#555}.shape-card h3{font-size:18px;margin:12px 0 2px}.shape-card .audience{font-size:12px;color:var(--green);font-weight:700}.shape-print-card{display:block;width:100%;height:auto;margin:12px 0 14px;border:1px solid var(--line);background:#fff}.mini-actions{display:grid;grid-template-columns:repeat(3,1fr);gap:6px;margin-top:auto}.mini-actions .btn{min-height:36px;font-size:12px;border-color:#999}.sheet-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-bottom:8px}.sheet-card{border:1px solid var(--line);border-radius:9px;padding:20px;display:flex;flex-direction:column;gap:12px}.sheet-card__head h3{font-size:19px;margin:0 0 2px}.sheet-card__head .audience{font-size:12px;color:var(--green);font-weight:700;margin:0}.sheet-card__image{display:block;width:100%;height:auto;border:1px solid var(--line);background:#fff}.sheet-card__text{color:var(--muted);font-size:15px;margin:0}.sheet-card__actions{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;margin-top:auto}.sheet-card__actions .btn{min-height:38px;font-size:13px;padding:0 6px}.sheet-card__source{color:var(--accent);font-weight:700;font-size:14px}.key-switcher{display:flex;align-items:center;gap:16px;flex-wrap:wrap;border:1px solid var(--line);border-radius:9px;padding:14px 18px;margin-bottom:8px;background:var(--soft)}.key-switcher__label{font-weight:800;font-size:14px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}.key-switcher__buttons{display:flex;gap:6px;flex-wrap:wrap}.key-chip{min-width:46px;min-height:38px;border:1px solid #bbb;border-radius:6px;background:#fff;font:700 15px/1 inherit;color:var(--ink);cursor:pointer}.key-chip:hover{border-color:var(--ink)}.key-chip[aria-pressed=true]{background:var(--ink);color:#fff;border-color:var(--ink)}.scale-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:32px;align-items:start}.neck-wrap svg.neck{width:100%;height:auto;display:block}.scale-facts{display:flex;gap:28px;flex-wrap:wrap;margin:18px 0 14px;font-size:15px;color:#333}.scale-facts b{display:block;font-size:12px;text-transform:uppercase;letter-spacing:.07em;color:var(--muted)}.scale-actions{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.scale-actions .btn{min-height:46px;font-size:14px}.scale-print{border:1px solid var(--line);border-radius:9px;background:var(--soft);padding:18px}.box-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:22px}.box-card{border:1px solid var(--line);border-radius:9px;padding:20px}.box-card h3{font-size:20px;margin:0 0 2px}.box-card .audience{font-size:12px;color:var(--green);font-weight:700;margin:0 0 10px}.box-card p{color:var(--muted);font-size:15px}.box-card .neck-wrap{margin-bottom:10px}.prose{max-width:820px}.prose p{font-size:17px;color:#333}.facts-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px}.info-card{border:1px solid var(--line);border-radius:9px;padding:26px}.info-card h3{font-size:20px;margin:0 0 15px}.note-row{display:flex;gap:10px;margin-bottom:14px}.note-chip{width:46px;height:46px;border-radius:50%;display:grid;place-items:center;background:#111;color:#fff;font-weight:800}.key-list{display:flex;gap:9px;flex-wrap:wrap;margin-bottom:14px}.key-list span{border:1px solid #bbb;border-radius:5px;padding:9px 12px;font-weight:700;font-size:15px}.info-card p{margin:0;color:var(--muted)}.next-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}.next-card{border:1px solid var(--line);border-radius:9px;display:grid;grid-template-columns:200px 1fr;align-items:center;gap:24px;padding:22px 28px}.next-card .diagram{width:100%}.next-card h3{font-size:25px;margin:0 0 8px}.next-card p{color:var(--muted);margin:0 0 12px}.next-card a{color:var(--accent);font-weight:800}.faq details{border:1px solid var(--line);padding:16px 18px;margin-top:-1px}.faq summary{font-weight:700;cursor:pointer}.faq p{margin:12px 0 2px;color:#3f3f3d;max-width:900px}footer.site-footer{border-top:1px solid #e5e5e2;margin-top:40px;padding:28px 0 40px;font-size:14px}@media(max-width:1080px){.compare-grid,.card-grid,.sheet-grid{grid-template-columns:repeat(2,1fr)}.feature{grid-template-columns:1fr;gap:32px}.intro{border-left:0;padding-left:0}}@media(max-width:1180px){.site-nav{gap:20px;font-size:14px}.header-row{gap:24px}}@media(max-width:950px){:root{--shell: calc(100% - 36px) }.site-nav{display:none}.variant-panel[data-active]{grid-template-columns:1fr}.diagram-side{grid-template-columns:1fr;padding:24px}.artifact-side{border-left:0;border-top:1px solid var(--line)}.next-grid,.facts-grid,.scale-layout,.box-grid{grid-template-columns:1fr}.scale-actions,.tabs{grid-template-columns:repeat(2,1fr)}.tab:nth-child(2){border-right:0}}@media(max-width:620px){.chord-grid,.artifact-bar,.variant-actions{grid-template-columns:repeat(2,1fr)}.next-card{grid-template-columns:1fr}}.print-sheet{display:none}@media print{body>*:not(.print-region){display:none!important}.print-region{display:block!important}.print-sheet{display:block;break-after:page;page-break-after:always}.print-sheet:last-child{break-after:auto;page-break-after:auto}.print-sheet svg{width:100%;height:auto;max-height:96vh}.print-scope-single .print-sheet:not(.is-print-target){display:none}@page{margin:12mm}}.text-page{max-width:760px}.text-page section{margin-bottom:34px}.text-page h2{font-size:22px;letter-spacing:-.4px;margin:0 0 10px}.text-page p{font-size:17px;color:#333}.text-page__contact{font-weight:700}.text-page__contact a{color:var(--accent)}.footer-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:32px;padding-bottom:26px}.footer-grid nav{display:flex;flex-direction:column;gap:8px;align-items:flex-start}.footer-grid h2{font-size:12px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:0 0 4px}.footer-grid a{color:#333}.footer-grid a:hover{color:var(--accent)}.footer-legal{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap;border-top:1px solid #ececea;padding-top:18px;color:var(--muted)}@media(max-width:720px){.footer-grid{grid-template-columns:1fr 1fr}}.key-gallery__title{font-size:18px;margin:34px 0 14px}.key-gallery__title span{font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.07em;color:var(--muted);margin-left:8px}.key-gallery{list-style:none;margin:0 0 8px;padding:0;display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:12px}.key-gallery a{display:block;text-align:center}.key-gallery img{display:block;width:100%;height:auto;border:1px solid var(--line);background:#fff}.key-gallery a:hover img{border-color:var(--ink)}.key-gallery span{display:block;font-weight:700;font-size:14px;margin-top:6px}@media(max-width:1080px){.key-gallery{grid-template-columns:repeat(6,minmax(0,1fr))}}@media(max-width:620px){.key-gallery{grid-template-columns:repeat(4,minmax(0,1fr))}}.action-note{grid-column:1 / -1;margin:4px 0 0;font-size:14px;color:var(--muted);text-align:center}.teacher-note{border-left:3px solid var(--accent);padding:2px 0 2px 16px;margin:22px 0;color:#333;max-width:640px}.teacher-note a{color:var(--accent);font-weight:700}
