:root{--desk:#f1ebdd;--paper:#fffdf7;--ink:#17212b;--muted:#66707a;--line:#cbc5b8;--grid:#ddd8cc;--blue:#2764e7;--yellow:#ffd84d;--green:#209b68;--orange:#ee7b32;--red:#d94a43;--font-ui:"HarmonyOS Sans SC", "MiSans", "Noto Sans SC", "Microsoft YaHei UI", system-ui, sans-serif;--font-tech:"IBM Plex Mono", "JetBrains Mono", "Cascadia Mono", Consolas, monospace;--ease:cubic-bezier(.22, .8, .24, 1)}*{box-sizing:border-box}html{scroll-behavior:smooth;background:var(--desk)}body{background:linear-gradient(90deg, #ffffff38 1px, transparent 1px) 0 0 / 72px 72px, var(--desk);color:var(--ink);font-family:var(--font-ui);margin:0;font-size:16px;line-height:1.65}button,a{font:inherit}button{color:inherit}button:disabled{opacity:.48;cursor:not-allowed!important}a{color:inherit;text-decoration:none}button,a,[tabindex]{-webkit-tap-highlight-color:transparent}:focus-visible{outline:3px solid var(--blue);outline-offset:4px}.site-shell{min-height:100vh;overflow:clip}.section-wrap,.workbench{width:min(1240px,100% - 64px);margin-inline:auto}.tool-rail{z-index:50;border-bottom:2px solid var(--ink);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);background:#ebe4d6f5;grid-template-columns:minmax(200px,1fr) auto minmax(160px,1fr);align-items:center;gap:28px;min-height:72px;padding:0 max(32px,50vw - 620px);display:grid;position:sticky;top:0;box-shadow:0 4px #17212b0f}.brand{width:fit-content;font-family:var(--font-tech);letter-spacing:.08em;align-items:center;gap:13px;font-size:.92rem;font-weight:800;display:inline-flex}.brand-mark{background:var(--ink);grid-template-columns:repeat(2,12px);gap:2px;width:30px;height:30px;padding:2px;display:grid;position:relative;transform:rotate(-3deg)}.brand-mark i:first-child{background:#ffd43b}.brand-mark i:nth-child(2){background:#e4493e}.brand-mark i:nth-child(3){background:#24a568}.brand-mark i:nth-child(4){background:#2d67d7}.rail-nav{align-items:center;gap:28px;font-size:.88rem;font-weight:700;display:flex}.rail-nav a{padding:22px 0 20px;position:relative}.rail-nav a:after{content:"";background:var(--blue);height:2px;transition:right .16s var(--ease);position:absolute;bottom:15px;left:0;right:100%}.rail-nav a:hover:after{right:0}.rail-progress{font-family:var(--font-tech);text-transform:uppercase;justify-self:end;align-items:baseline;gap:10px;font-size:.72rem;display:flex}.rail-progress strong{color:var(--blue);font-size:1rem}.hero{grid-template-columns:5fr 7fr;align-items:center;gap:54px;min-height:680px;padding-block:64px 76px;display:grid}.hero-copy{z-index:2;position:relative}.eyebrow{color:var(--blue);font-family:var(--font-tech);letter-spacing:.13em;text-transform:uppercase;margin:0 0 16px;font-size:.73rem;font-weight:800}h1,h2,h3,p{text-wrap:pretty}h1,h2,h3{letter-spacing:-.035em;margin-top:0;line-height:1.12}h1{max-width:660px;margin-bottom:25px;font-size:clamp(3rem,5.2vw,5.4rem);font-weight:850}h2{margin-bottom:18px;font-size:clamp(2rem,3.4vw,3.6rem);font-weight:820}.hero-lead{color:#4f5c67;max-width:510px;margin:0 0 30px;font-size:1.08rem;line-height:1.85}.hero-actions,.finish-actions{align-items:center;gap:24px;display:flex}.mechanical-button{border:2px solid var(--ink);background:var(--paper);min-height:48px;box-shadow:3px 4px 0 var(--ink);cursor:pointer;transition:transform .16s var(--ease), box-shadow .16s var(--ease), background .16s;border-radius:8px;justify-content:center;align-items:center;gap:10px;padding:10px 22px;font-weight:800;display:inline-flex}.mechanical-button:hover{transform:translateY(-2px)}.mechanical-button:active{box-shadow:none;transform:translate(3px,4px)}.mechanical-button--primary{color:#fff;background:var(--blue)}.mechanical-button--yellow{background:var(--yellow)}.mechanical-button--small{color:#fff;background:var(--blue);min-height:42px;box-shadow:3px 3px 0 var(--ink);padding:7px 20px}.text-button{border:0;border-bottom:1px solid var(--ink);cursor:pointer;background:0 0;font-weight:750}.quiet-note{color:var(--muted);margin:25px 0 20px;font-size:.82rem}.bench-rule{width:min(430px,100%);color:var(--muted);font-family:var(--font-tech);align-items:center;gap:12px;font-size:.68rem;display:flex}.bench-rule i{background:repeating-linear-gradient(90deg, var(--ink) 0 1px, transparent 1px 18px);border-bottom:1px solid var(--ink);flex:1;height:9px}.cube-rig{aspect-ratio:1;background-color:#e8e2d4;background-image:linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px);border:2px solid var(--ink);background-size:24px 24px;border-radius:5px;justify-self:end;place-items:center;width:min(540px,100%);display:grid;position:relative;box-shadow:14px 16px #17212b1f}.cube-rig:before,.cube-rig:after{content:"";background:#17212b52;position:absolute}.cube-rig:before{width:1px;height:76%;top:12%;left:50%}.cube-rig:after{width:76%;height:1px;top:50%;left:12%}.goal-note{z-index:8;background:#fff2a9;border:1px solid #17212b2e;min-width:176px;padding:10px 15px 12px;position:absolute;top:22px;left:20px;transform:rotate(-1.6deg);box-shadow:0 7px 14px #23282c1f}.goal-note:before{content:"";background:#ffffff94;width:68px;height:14px;position:absolute;top:-7px;left:54px;transform:rotate(2deg)}.goal-note small,.goal-note strong{display:block}.goal-note small{color:var(--muted);font-size:.7rem}.goal-note strong{font-size:1rem}.axis-label{z-index:3;border:1px solid var(--ink);background:var(--paper);width:26px;height:26px;font-family:var(--font-tech);place-items:center;font-size:.72rem;font-weight:800;display:grid;position:absolute}.axis-label--u{top:22%;left:51%}.axis-label--f{bottom:30%;left:18%}.axis-label--r{bottom:38%;right:17%}.cube-scene{--face-size:192px;--face-half:98px;--cell-step:calc((var(--face-size) - 11px) / 3);--sticker-size:calc((var(--face-size) - 26px) / 3);--sticker-depth:calc(var(--face-half) + 2px);z-index:5;perspective:900px;cursor:grab;touch-action:none;-webkit-user-select:none;user-select:none;place-items:center;width:330px;height:330px;display:grid;position:relative}.cube-scene:active{cursor:grabbing}.cube-scene:before{content:"";filter:blur(17px);pointer-events:none;background:#1d232847;border-radius:50%;width:62%;height:18%;position:absolute;top:68%;left:50%;transform:translate(-50%,-50%)rotate(-4deg)}.cube-scene--compact{--face-size:154px;--face-half:79px;width:270px;height:270px}.cube{z-index:1;width:var(--face-size);height:var(--face-size);transform-style:preserve-3d;transform:rotateX(var(--cube-pitch)) rotateY(var(--cube-yaw));will-change:transform;position:relative}.cube-face{width:var(--face-size);height:var(--face-size);backface-visibility:hidden;background:#111820;border:2px solid #06090c;border-radius:10px;position:absolute;inset:0}.cube-sticker-field,.cube-turn-layer{transform-style:preserve-3d;pointer-events:none;position:absolute;inset:0}.cube-turn-layer{transform-origin:50% 50% 0;animation:cube-layer-turn var(--turn-duration) cubic-bezier(.32, .72, .2, 1) forwards;will-change:transform}.cube-sticker-position{width:0;height:0;transform-style:preserve-3d;position:absolute;top:50%;left:50%}.cube-sticker-3d{width:var(--sticker-size);height:var(--sticker-size);backface-visibility:hidden;border:1px solid #0000003d;border-radius:7px;display:block;position:absolute;top:0;left:0;transform:translate(-50%,-50%);box-shadow:inset 0 3px #fff3,inset 0 -3px #0000001f}@keyframes cube-layer-turn{0%{transform:rotate3d(var(--turn-x), var(--turn-y), var(--turn-z), 0deg)}to{transform:rotate3d(var(--turn-x), var(--turn-y), var(--turn-z), var(--turn-angle))}}.cube-face--f{transform:translateZ(var(--face-half))}.cube-face--b{transform:rotateY(180deg) translateZ(var(--face-half))}.cube-face--r{transform:rotateY(90deg) translateZ(var(--face-half))}.cube-face--l{transform:rotateY(-90deg) translateZ(var(--face-half))}.cube-face--u{transform:rotateX(90deg) translateZ(var(--face-half))}.cube-face--d{transform:rotateX(-90deg) translateZ(var(--face-half))}.cube-turn-cue{z-index:8;border:1px solid var(--ink);background:var(--paper);min-width:76px;min-height:34px;box-shadow:3px 3px 0 var(--ink);animation:cube-turn-cue-in .16s var(--ease);pointer-events:none;border-radius:5px;justify-content:center;align-items:center;gap:9px;padding:4px 11px;display:flex;position:absolute;top:9px;left:50%;transform:translate(-50%)}.cube-turn-cue strong{color:var(--blue);font-family:var(--font-tech);font-size:.92rem}.cube-turn-cue i{font-style:normal;font-weight:900}@keyframes cube-turn-cue-in{0%{opacity:0;transform:translate(-50%,-6px)}to{opacity:1;transform:translate(-50%)}}.cube-drag-hint{color:var(--muted);white-space:nowrap;background:#fffdf7cc;padding:3px 9px;font-size:.66rem;position:absolute;bottom:4px;left:50%;transform:translate(-50%)}.rig-controls{z-index:9;gap:7px;display:flex;position:absolute;bottom:22px;left:22px}.rig-controls button,.speed-switch button{border:1px solid var(--ink);background:var(--paper);min-width:42px;min-height:38px;box-shadow:2px 2px 0 var(--ink);cursor:pointer;border-radius:5px;padding:4px 10px;font-weight:750}.rig-controls .rig-play{color:#fff;background:var(--blue)}.speed-switch{z-index:9;display:flex;position:absolute;bottom:22px;right:18px}.speed-switch button{min-width:39px;box-shadow:none;font-family:var(--font-tech);border-radius:0;font-size:.66rem}.speed-switch button+button{border-left:0}.speed-switch button:first-child{border-radius:5px 0 0 5px}.speed-switch button:last-child{border-radius:0 5px 5px 0}.speed-switch button.active{color:#fff;background:var(--ink)}.notation-section,.lesson-section,.trainer-section,.timer-section{scroll-margin-top:92px}.notation-section{border-top:1px solid #17212b2e;padding-block:92px 110px}.section-heading{grid-template-columns:1.6fr 1fr;align-items:end;gap:64px;margin-bottom:42px;display:grid}.section-heading h2{margin-bottom:0}.section-heading>p{color:var(--muted);margin:0 0 5px}.section-heading--split{grid-template-columns:1fr auto}.parts-drawer{border:2px solid var(--ink);background:#ddd5c5;grid-template-columns:repeat(6,1fr);gap:12px;padding:18px;display:grid;box-shadow:inset 0 7px 18px #17212b1c,8px 9px #17212b1a}.notation-card{border:1px solid var(--line);background:var(--paper);text-align:left;cursor:pointer;min-height:224px;transition:transform .16s var(--ease), border-color .16s, box-shadow .16s;border-radius:8px;grid-template-rows:1fr auto auto;grid-template-columns:1fr auto;align-items:start;gap:7px;padding:17px;display:grid;position:relative;box-shadow:0 8px 16px #23282c14}.notation-card:hover{transform:translateY(-3px)}.notation-card.active{border:2px solid var(--blue);transform:translateY(-5px);box-shadow:0 10px #2764e721}.notation-letter{font-family:var(--font-tech);font-size:3.4rem;font-weight:850;line-height:1}.notation-name{grid-column:1/-1;font-weight:800}.notation-direction{color:var(--muted);grid-column:1/-1;font-size:.7rem}.mini-cube{background:var(--ink);border:1px solid var(--ink);grid-template-columns:repeat(3,1fr);gap:2px;width:54px;height:54px;padding:3px;display:grid;transform:rotate(2deg)}.mini-cube i{border:1px solid #00000029}.notation-legend{align-items:center;gap:26px;padding:22px 4px 0;font-size:.86rem;display:flex}.notation-legend span{white-space:nowrap}.notation-legend strong{font-family:var(--font-tech);margin-right:6px;font-size:1.15rem}.notation-legend p{color:var(--blue);margin:0 0 0 auto;font-style:italic}.lesson-section{border-top:2px solid var(--ink);padding-block:100px 120px}.progress-copy{min-width:220px;font-family:var(--font-tech);grid-template-columns:1fr auto;gap:4px 18px;font-size:.74rem;display:grid}.progress-copy strong{color:var(--blue);font-size:1.1rem}.progress-track{border:1px solid var(--ink);background:#d6cfbf;grid-column:1/-1;height:7px;overflow:hidden}.progress-track i{background:var(--green);height:100%;transition:width .24s var(--ease);display:block}.lesson-board{grid-template-columns:repeat(4,1fr);align-items:start;gap:23px;display:grid}.lesson-card{--lesson-color:#ffd43b;border:1px solid var(--line);background:var(--paper);min-height:354px;transition:transform .18s var(--ease), border-color .18s, box-shadow .18s;border-radius:12px;position:relative;overflow:visible;box-shadow:0 10px 24px #23282c14}.lesson-card:nth-child(odd){transform:rotate(-.35deg)}.lesson-card:nth-child(2n){transform:rotate(.42deg)}.lesson-card:hover{transform:translateY(-3px)rotate(0)}.lesson-card.selected{border:2px solid var(--blue);box-shadow:8px 9px #2764e726}.lesson-card.complete:after{content:"已掌握";z-index:6;color:var(--green);border:3px double var(--green);animation:stamp .24s var(--ease);padding:3px 8px;font-size:.72rem;font-weight:900;position:absolute;top:18px;right:14px;transform:rotate(-7deg)}@keyframes stamp{0%{opacity:0;transform:rotate(-7deg)scale(1.18)}}.card-clip{z-index:5;border:3px solid var(--blue);border-bottom:0;border-radius:12px 12px 0 0;width:48px;height:22px;position:absolute;top:-12px;left:50%;transform:translate(-50%)}.lesson-card__open{text-align:left;cursor:pointer;background:0 0;border:0;flex-direction:column;align-items:flex-start;width:100%;min-height:305px;padding:22px 22px 14px;display:flex}.step-number,.lesson-meta{font-family:var(--font-tech);letter-spacing:.08em;font-size:.66rem}.step-number{color:var(--blue);font-weight:800}.lesson-visual{background:var(--ink);grid-template-columns:repeat(3,1fr);gap:3px;width:70px;height:70px;margin:18px 0 15px;padding:4px;display:grid;transform:rotate(-2deg)}.lesson-visual i{background:#2b3540}.lesson-visual i:nth-child(2),.lesson-visual i:nth-child(4),.lesson-visual i:nth-child(5),.lesson-visual i:nth-child(6),.lesson-visual i:nth-child(8){background:var(--lesson-color)}.lesson-card--1,.lesson-card--2{--lesson-color:#f8f8f2}.lesson-card--3{--lesson-color:#24a568}.lesson-card--4,.lesson-card--5,.lesson-card--6,.lesson-card--7{--lesson-color:#ffd43b}.lesson-card__open>strong{font-size:1.24rem}.lesson-card__open>small{color:var(--muted);font-family:var(--font-tech);font-size:.62rem}.lesson-card__open p{color:var(--muted);margin:12px 0 14px;font-size:.84rem;line-height:1.65}.lesson-meta{color:var(--muted);margin-top:auto}.complete-toggle{border:1px dashed var(--line);width:calc(100% - 32px);min-height:34px;color:var(--muted);cursor:pointer;background:#f8f4eb;border-radius:5px;margin:0 16px 15px;font-size:.73rem;font-weight:750}.complete-toggle[aria-pressed=true]{color:var(--green);border-color:var(--green);background:#eef8f2}.trainer-section{background-color:var(--paper);border:2px solid var(--ink);background-image:linear-gradient(#ddd8cc7a 1px,#0000 1px),linear-gradient(90deg,#ddd8cc7a 1px,#0000 1px);background-size:24px 24px;margin-bottom:112px;padding:64px;position:relative;transform:rotate(-.12deg);box-shadow:16px 18px #17212b21}.trainer-section:focus-visible{outline-offset:7px}.sheet-pin{border:2px solid var(--ink);background:#a7a39a;border-radius:50%;width:15px;height:15px;position:absolute;top:18px;box-shadow:inset 2px 2px #ffffff80,2px 3px 4px #17212b3d}.sheet-pin--left{left:24px}.sheet-pin--right{right:24px}.trainer-heading{border-bottom:2px solid var(--ink);justify-content:space-between;align-items:end;gap:30px;padding-bottom:26px;display:flex}.trainer-heading h2{margin-bottom:0}.trainer-status{align-items:flex-end;gap:22px;display:flex}.trainer-speed-control{border:1px solid var(--ink);background:var(--paper);border-radius:5px;display:flex;overflow:hidden}.trainer-speed-control button{min-height:42px;font-family:var(--font-tech);cursor:pointer;background:0 0;border:0;gap:0;padding:5px 10px;display:grid}.trainer-speed-control button+button{border-left:1px solid var(--ink)}.trainer-speed-control button.active{color:#fff;background:var(--ink)}.trainer-speed-control span{font-size:.55rem;line-height:1.2}.trainer-speed-control strong{font-size:.68rem}.trainer-step-count{text-align:right;font-family:var(--font-tech)}.trainer-step-count span{color:var(--muted);font-size:.68rem;display:block}.trainer-step-count strong{font-size:1.35rem}.trainer-grid{grid-template-columns:1.08fr .92fr;gap:54px;padding-block:38px;display:grid}.trainer-cube-pad{border:1px solid var(--line);background:#e5e0d4b8;align-content:center;place-items:center;min-height:370px;display:grid}.trainer-buttons{justify-content:center;align-items:center;gap:18px;display:flex}.trainer-buttons>button:not(.mechanical-button){cursor:pointer;background:0 0;border:0;min-height:42px;font-weight:750}.lesson-notes{align-self:center;padding:18px 8px 18px 0}.paper-label{background:var(--yellow);font-family:var(--font-tech);margin-bottom:22px;padding:4px 12px;font-size:.72rem;font-weight:800;display:inline-block;transform:rotate(-1deg)}.lesson-notes h3{margin-bottom:16px;font-size:clamp(1.65rem,3vw,2.45rem)}.lesson-notes>p{color:var(--muted);font-size:.96rem}.lesson-notes dl{gap:16px;margin:28px 0;display:grid}.lesson-notes dl div{border-left:4px solid var(--blue);background:#2764e70f;padding:13px 16px}.lesson-notes dl .mistake-note{border-left-color:var(--orange);background:#ee7b3214}.lesson-notes dt{margin-bottom:3px;font-size:.72rem;font-weight:850}.lesson-notes dd{color:#4e5963;margin:0;font-size:.86rem}.reset-link{color:var(--blue);cursor:pointer;background:0 0;border:0;border-bottom:1px solid;padding:0;font-weight:750}.formula-bench{border-top:2px solid var(--ink);padding-top:24px}.formula-bench__top{justify-content:space-between;gap:20px;margin-bottom:14px;font-size:.75rem;font-weight:800;display:flex}.hotkey-note{color:var(--muted);font-family:var(--font-tech);font-weight:500}.formula-track{scrollbar-color:var(--ink) transparent;align-items:stretch;gap:9px;padding:7px 4px 16px;display:flex;overflow-x:auto}.formula-token{border:1px solid var(--line);cursor:pointer;min-height:74px;transition:transform .16s var(--ease), background .16s, border-color .16s;background:#f5f1e8;flex:0 0 69px;place-items:center;gap:1px;padding:8px;display:grid;position:relative;overflow:hidden}.formula-token:hover{transform:translateY(-2px)}.formula-token strong{font-family:var(--font-tech);font-size:1.45rem}.formula-token small{color:var(--muted);font-family:var(--font-tech);font-size:.58rem}.formula-token--done{color:#8c918f;text-decoration:underline;text-decoration-thickness:1px}.formula-token--current{background:var(--yellow);border:2px solid var(--ink);transform:rotate(-1.5deg)translateY(-3px)}.formula-token--next{border:2px solid var(--blue)}.formula-token--animating:disabled{opacity:1}.formula-token--animating:after{content:"";background:var(--blue);transform-origin:0;height:4px;animation:formula-turn-progress var(--turn-duration) linear forwards;position:absolute;bottom:0;left:0;right:0;transform:scaleX(0)}@keyframes formula-turn-progress{to{transform:scaleX(1)}}.move-instruction{border-left:4px solid var(--blue);color:var(--blue);background:#2764e70f;margin:4px 0 0;padding:10px 14px;font-size:.86rem;font-weight:700}.move-instruction.complete{color:var(--green);border-left-color:var(--green);background:#209b6814}.timer-section{border-top:2px solid var(--ink);grid-template-columns:6fr 3fr 3fr;align-items:center;gap:36px;padding-block:80px 120px;display:grid}.timer-intro h2{max-width:620px}.timer-intro>p:not(.eyebrow){max-width:570px;color:var(--muted)}.scramble-strip{background:var(--paper);border:1px solid var(--line);margin-top:28px;padding:14px 16px 13px 22px;position:relative;transform:rotate(-.6deg);box-shadow:5px 6px #17212b14}.scramble-strip:before{content:"";background:var(--red);width:1px;position:absolute;top:0;bottom:0;left:7px}.scramble-strip>span{color:var(--muted);margin-bottom:6px;font-size:.66rem;font-weight:800;display:block}.scramble-strip code{font-family:var(--font-tech);font-size:.85rem;line-height:1.75;display:block}.scramble-strip>div{gap:14px;margin-top:9px;display:flex}.scramble-strip button{cursor:pointer;background:0 0;border:0;border-bottom:1px solid;padding:0;font-size:.7rem;font-weight:750}.stopwatch{aspect-ratio:.86;border:3px solid var(--ink);background:#e5e1d8;border-radius:50% 50% 44% 44%;align-content:center;place-items:center;gap:12px;width:100%;padding:30px 18px 22px;display:grid;position:relative;box-shadow:inset 0 0 0 7px #f8f6f0,8px 9px #17212b26}.stopwatch-crown{border:3px solid var(--ink);background:#b9b6ae;border-bottom:0;width:52px;height:29px;position:absolute;top:-25px;left:50%;transform:translate(-50%)}.stopwatch small{font-family:var(--font-tech);letter-spacing:.12em;font-weight:800}.stopwatch output{font-family:var(--font-tech);letter-spacing:-.05em;font-size:clamp(1.75rem,3vw,2.8rem);font-weight:800}.stopwatch--ready output{color:var(--green)}.stopwatch--running output{color:var(--blue)}.timer-button{border:2px solid var(--ink);background:var(--yellow);min-height:45px;box-shadow:2px 3px 0 var(--ink);cursor:pointer;border-radius:6px;padding:8px 14px;font-size:.75rem;font-weight:850}.stopwatch--running .timer-button{color:#fff;background:var(--red)}.time-slips{gap:12px;display:grid}.time-slips>div{background:var(--paper);border-left:4px solid var(--blue);gap:2px;padding:13px 15px;display:grid;box-shadow:4px 4px #17212b14}.time-slips>div:nth-child(2){border-left-color:var(--green);transform:rotate(.8deg)}.time-slips>div:nth-child(3){border-left-color:var(--orange);transform:rotate(-.5deg)}.time-slips span{color:var(--muted);font-size:.65rem}.time-slips strong{font-family:var(--font-tech);font-size:1.2rem}.time-slips p{color:var(--muted);margin:5px 0 0;font-size:.72rem}.finish-card{color:#fff;background:var(--ink);border:2px solid var(--ink);grid-template-columns:1.25fr .75fr;align-items:end;gap:50px;margin-bottom:92px;padding:58px 64px;display:grid;box-shadow:12px 14px #17212b24}.finish-card .eyebrow{color:var(--yellow)}.finish-card h2{margin-bottom:14px}.finish-card 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