.ac-wrap{max-width:1140px;margin:0 auto;padding:2.4rem var(--container-padding) 5rem;color:var(--ink)}
.ac-breadcrumb{font-size:.78rem;color:var(--ink-60);margin:0 0 1.65rem}.ac-breadcrumb a{color:var(--ink-70)}.ac-breadcrumb span{margin:0 .45rem}
.ac-eyebrow{display:inline-block;font-size:.72rem;font-weight:700;letter-spacing:.11em;text-transform:uppercase;color:var(--negative-strong);margin-bottom:.7rem}
.ac-hero{max-width:810px;margin-bottom:2.4rem}.ac-hero h1{font-family:var(--font-display);font-size:clamp(2.5rem,5vw,4rem);line-height:1.03;margin:0 0 .8rem;color:var(--ink)}.ac-hero p{color:var(--ink-70);font-size:1.08rem;line-height:1.65;margin:0}
.ac-paths{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1rem;margin:0 5px 3rem 0}.ac-path{display:flex;flex-direction:column;align-items:flex-start;padding:1.55rem;background:var(--surface);border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);box-shadow:var(--shadow-chip);text-decoration:none;color:var(--ink);min-height:260px}.ac-path:hover,.ac-path:focus-visible{background:var(--wash-2)}.ac-path-tag{font-size:.68rem;letter-spacing:.09em;font-weight:700;text-transform:uppercase;color:var(--ink-70);margin-bottom:1.2rem}.ac-path h2{font-family:var(--font-display);font-size:2rem;line-height:1.1;margin:0 0 .6rem}.ac-path p{font-size:.93rem;line-height:1.55;color:var(--ink-70);margin:0 0 1.3rem}.ac-path-cta{margin-top:auto;font-size:.79rem;font-weight:700;color:var(--negative-strong)}
.ac-section{margin:0 0 2.6rem}.ac-section h2{font-family:var(--font-display);font-size:1.8rem;margin:0 0 .6rem}.ac-section-intro{color:var(--ink-70);max-width:720px;line-height:1.6;margin:0 0 1.3rem}
.ac-step-list{list-style:none;padding:0;margin:0;display:grid;gap:.6rem}.ac-step-list a{display:grid;grid-template-columns:2.2rem minmax(0,1fr) auto;align-items:center;gap:.85rem;padding:.85rem 1rem;color:var(--ink);text-decoration:none;background:var(--surface);border:1px solid var(--rule);border-radius:var(--r-sm)}.ac-step-list a:hover,.ac-step-list a:focus-visible{border-color:var(--keyline);box-shadow:var(--chip-sm) var(--keyline)}.ac-num{font-variant-numeric:tabular-nums;font-weight:700;color:var(--negative-strong)}.ac-step-list strong{display:block;font-size:.92rem}.ac-step-list small{display:block;font-size:.78rem;color:var(--ink-70);line-height:1.45;margin-top:.18rem}.ac-arrow{font-size:1.15rem}
.ac-split{display:grid;grid-template-columns:minmax(0,1fr) 270px;gap:2rem;align-items:start}.ac-article{min-width:0;max-width:760px}.ac-article h2{font-family:var(--font-display);font-size:1.7rem;line-height:1.2;margin:2.25rem 0 .7rem}.ac-article h3{font-size:1rem;margin:1.5rem 0 .45rem}.ac-article p,.ac-article li{font-size:.96rem;line-height:1.72;color:var(--ink-70)}.ac-article p{margin:.7rem 0 1.1rem}.ac-article li{margin:.4rem 0}.ac-article a{color:var(--info-strong);text-underline-offset:2px}.ac-article strong{color:var(--ink)}.ac-article ul,.ac-article ol{padding-left:1.4rem}.ac-answer{font-size:1.1rem!important;color:var(--ink)!important;border-left:var(--keyline-w) solid var(--coral);padding-left:1rem;margin:1.2rem 0 2rem!important}.ac-note{background:var(--wash);border:1px solid var(--rule);border-radius:var(--r-sm);padding:1rem 1.1rem;margin:1.5rem 0}.ac-note p:last-child{margin-bottom:0}.ac-note strong{display:block;margin-bottom:.25rem}.ac-table-wrap{overflow-x:auto;margin:1.3rem 0}.ac-table{width:100%;border-collapse:collapse;min-width:520px;font-size:.87rem}.ac-table th,.ac-table td{text-align:left;padding:.75rem;border-bottom:1px solid var(--rule);vertical-align:top}.ac-table th{background:var(--wash);color:var(--ink);font-weight:700}.ac-table td{color:var(--ink-70)}
.ac-rail{position:sticky;top:1.5rem;border-left:2px solid var(--rule);padding-left:1rem}.ac-rail strong{font-size:.8rem}.ac-rail ol{padding-left:1.25rem;margin:.7rem 0}.ac-rail li{font-size:.78rem;line-height:1.4;margin:.55rem 0;color:var(--ink-70)}.ac-rail a{color:var(--ink-70);text-decoration:none}.ac-rail a:hover{text-decoration:underline}.ac-rail [aria-current=page]{font-weight:700;color:var(--negative-strong)}
.ac-quiz{border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);background:var(--surface);box-shadow:var(--chip-md) var(--keyline);padding:1.25rem;margin:2.3rem 4px 1.5rem 0}.ac-quiz h2{margin:0 0 .5rem}.ac-quiz fieldset{border:0;padding:0;margin:1.1rem 0}.ac-quiz legend{font-weight:700;line-height:1.5;margin-bottom:.6rem}.ac-option{display:block;padding:.65rem .7rem;border:1px solid var(--rule);border-radius:var(--r-sm);margin:.45rem 0;cursor:pointer;color:var(--ink-70);font-size:.88rem}.ac-option:has(input:checked){border-color:var(--keyline);background:var(--wash-2)}.ac-option input{accent-color:var(--negative-strong);margin-right:.45rem}.ac-quiz button,.ac-button{display:inline-block;font-family:var(--font-body);font-size:.8rem;font-weight:700;color:var(--surface);background:var(--ink);border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);padding:.65rem .95rem;text-decoration:none;cursor:pointer}.ac-quiz button:hover,.ac-button:hover{background:var(--ink-strong);color:var(--surface)}.ac-feedback{font-size:.87rem;line-height:1.5;margin:.8rem 0 0!important}.ac-feedback[data-state=correct]{color:var(--positive-deep)}.ac-feedback[data-state=incorrect]{color:var(--negative-deep)}
.ac-next{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:1rem;border-top:1px solid var(--rule);padding-top:1.2rem;margin-top:2rem}.ac-next a{font-weight:700;color:var(--info-strong)}.ac-meta{font-size:.78rem!important;color:var(--ink-60)!important}.ac-pill{display:inline-block;background:var(--wash);border:1px solid var(--rule);border-radius:var(--r-pill);padding:.28rem .65rem;font-size:.69rem;font-weight:700;color:var(--ink-70)}
@media(max-width:820px){.ac-split{grid-template-columns:1fr}.ac-rail{position:static;border-left:0;border-top:2px solid var(--rule);padding:1rem 0 0}.ac-rail ol{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));column-gap:1rem}}@media(max-width:600px){.ac-wrap{padding-top:1.5rem}.ac-paths{grid-template-columns:1fr}.ac-path{min-height:215px}.ac-rail ol{grid-template-columns:1fr}.ac-step-list a{grid-template-columns:1.7rem minmax(0,1fr) auto;padding:.75rem}.ac-hero h1{font-size:2.45rem}}
.ac-note summary{cursor:pointer}
.ac-route{display:flex;flex-wrap:wrap;align-items:center;gap:.6rem;max-width:1140px;margin:0 auto;padding:.7rem var(--container-padding);background:var(--canvas);font:600 .76rem var(--font-body);color:var(--ink-70)}.ac-route a{color:var(--info-strong);text-decoration:underline;text-underline-offset:2px}.ac-route-other{margin-left:auto}
.ac-hero-action{margin-top:1rem!important;font-size:.78rem!important}.ac-hero-action a{display:inline-block;color:var(--info-strong);font-weight:700;text-underline-offset:2px}.ac-progress{font-size:.78rem;color:var(--ink-70);margin:0 0 .8rem}.ac-progress strong{color:var(--ink)}.ac-step-list .ac-passed{display:inline-block;color:var(--positive-deep);font-size:.69rem;font-weight:700;margin-top:.25rem}.ac-quiz{scroll-margin-top:1.5rem}
.ac-hero .ac-byline{font-size:.77rem;line-height:1.4;margin-top:.75rem;color:var(--ink-60)}.ac-byline a{color:var(--info-strong);text-underline-offset:2px}.ac-feedback-prompt{border-top:1px solid var(--rule);padding:1rem 0;margin:1.2rem 0}.ac-feedback-prompt h3{font-size:.95rem;margin:0 0 .25rem}.ac-feedback-prompt p{font-size:.78rem;margin:.2rem 0 .75rem}.ac-feedback-prompt [data-ac-feedback-options]{display:flex;flex-wrap:wrap;gap:.45rem}.ac-feedback-prompt button{font:700 .76rem var(--font-body);border:1px solid var(--keyline);border-radius:var(--r-sm);background:var(--surface);color:var(--ink);padding:.5rem .7rem;cursor:pointer}.ac-feedback-prompt button:hover,.ac-feedback-prompt button:focus-visible{background:var(--wash-2)}.ac-feedback-prompt [data-ac-feedback-result]{color:var(--positive-deep)}
.ac-feedback-prompt[hidden],.ac-feedback-prompt [hidden]{display:none!important}
.ac-journey>h2{scroll-margin-top:6rem}
.ac-basic{margin:2rem 0}.ac-basic>h2{scroll-margin-top:6rem;margin-top:.3rem}.ac-basic>p{max-width:680px}.ac-basic-card{background:var(--surface);border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);box-shadow:var(--chip-md) var(--keyline);padding:1.2rem;margin:0 4px 1rem 0}.ac-basic-card h3{font-family:var(--font-display);font-size:1.35rem;margin:.15rem 0 .45rem}.ac-basic-card p{margin:.4rem 0 .9rem}.ac-basic button{font:700 .8rem var(--font-body);background:var(--ink);color:var(--surface);border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);padding:.6rem .8rem;cursor:pointer}.ac-basic button:hover,.ac-basic button:focus-visible{background:var(--ink-strong)}.ac-basic button:disabled{background:var(--positive-deep);border-color:var(--positive-deep);cursor:default}.ac-basic button[aria-pressed=true]{background:var(--positive-deep);border-color:var(--positive-deep)}.ac-basic [hidden]{display:none!important}.ac-basic-result{background:var(--wash);border:1px solid var(--rule);border-radius:var(--r-sm);padding:1rem;margin-top:1rem}.ac-basic-result>strong{display:block}.ac-basic-result p:last-child{margin-bottom:0}.ac-basic-maths{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:.5rem}.ac-basic-maths span{display:block;background:var(--surface);border:1px solid var(--rule);border-radius:var(--r-sm);padding:.6rem;font-size:.78rem;color:var(--ink-70)}.ac-basic-maths strong{display:block;font-size:1.15rem;font-variant-numeric:tabular-nums}.ac-level-advanced{border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);background:var(--surface);box-shadow:var(--chip-md) var(--keyline);margin:2rem 4px 2rem 0}.ac-level-advanced>summary{cursor:pointer;list-style:none;padding:1.1rem 1.25rem}.ac-level-advanced>summary::-webkit-details-marker{display:none}.ac-level-advanced>summary span{display:block;color:var(--negative-strong);font-size:.7rem;font-weight:700;text-transform:uppercase;letter-spacing:.08em}.ac-level-advanced>summary strong{display:block;font-family:var(--font-display);font-size:1.45rem;margin:.2rem 0}.ac-level-advanced>summary small{display:block;color:var(--ink-70);font-size:.83rem;line-height:1.5}.ac-level-advanced>summary:hover,.ac-level-advanced>summary:focus-visible{background:var(--wash-2)}.ac-level-advanced-body{border-top:1px solid var(--rule);padding:0 1.25rem 1.25rem}.ac-level-advanced-body>h2:first-child{margin-top:1.4rem}@media(max-width:600px){.ac-basic-card{padding:1rem}.ac-basic-maths{grid-template-columns:1fr}.ac-level-advanced>summary,.ac-level-advanced-body{padding-left:1rem;padding-right:1rem}}
.ac-journey .ac-journey-restart:hover,.ac-journey .ac-journey-restart:focus-visible{background:var(--wash-2);color:var(--ink)}
.ac-journey-wallet{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:.5rem;margin:1rem 4px .6rem 0}.ac-journey-wallet>div{background:var(--wash);border:1px solid var(--rule);border-radius:var(--r-sm);padding:.7rem}.ac-journey-wallet span{display:block;color:var(--ink-70);font-size:.7rem;line-height:1.35}.ac-journey-wallet strong{display:block;color:var(--ink);font-size:1.05rem;font-variant-numeric:tabular-nums;margin-top:.25rem}.ac-journey .ac-journey-restart{background:var(--surface);color:var(--ink);padding:.4rem .65rem;margin:0 0 1rem}.ac-journey-slip{display:flex;align-items:center;flex-wrap:wrap;gap:.45rem .8rem;background:var(--wash-2);border:1px solid var(--rule);border-radius:var(--r-sm);padding:.8rem;margin:.8rem 0}.ac-journey-slip span{display:block;flex:1 1 100%;font-size:.74rem;color:var(--ink-70)}.ac-journey-slip strong{flex:1 1 180px;font-size:.9rem;font-variant-numeric:tabular-nums}.ac-journey-slip button{flex:0 1 auto}.ac-journey-slip button:disabled{opacity:1;background:var(--positive-deep);border-color:var(--positive-deep);color:var(--surface)}@media(max-width:620px){.ac-journey-wallet{grid-template-columns:repeat(2,minmax(0,1fr))}}
.ac-lay-guide{background:var(--wash);border:1px solid var(--rule);border-radius:var(--r-sm);padding:1rem;margin:0 0 1rem}.ac-lay-guide>strong{display:block;font-family:var(--font-display);font-size:1.2rem}.ac-lay-guide p{font-size:.85rem!important;line-height:1.6;margin:.55rem 0!important}.ac-lay-guide .ac-lay-formula{background:var(--surface);border-left:var(--keyline-w) solid var(--keyline);padding:.65rem .8rem;font-variant-numeric:tabular-nums;color:var(--ink)!important}.ac-lay-guide button{margin-top:.45rem}@media(max-width:520px){.ac-lay-guide{padding:.85rem}.ac-lay-guide button{width:100%}}
.ac-lay-maths{border-top:1px solid var(--rule);margin:.8rem 0;padding-top:.65rem}.ac-lay-maths summary{color:var(--info-strong);font-size:.83rem;font-weight:700;cursor:pointer}.ac-lay-maths summary:focus-visible,.ac-journey-optional>summary:focus-visible{outline:2px solid var(--info-strong);outline-offset:3px}.ac-lay-maths .ac-lay-formula{overflow-wrap:anywhere}
.ac-slip-pairs{display:grid;gap:1rem;margin:1.1rem 0 2rem}.ac-slip-pair{border:1px solid var(--rule);border-radius:var(--r-sm);background:var(--wash);padding:1rem}.ac-slip-pair h3{font-family:var(--font-display);font-size:1.2rem;margin:0 0 .7rem}.ac-slip-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.7rem}.ac-slip{background:var(--surface);border:1px solid var(--keyline);border-radius:var(--r-sm);padding:.8rem;min-width:0}.ac-slip span{display:block;color:var(--negative-strong);font-size:.7rem;font-weight:700;letter-spacing:.07em;text-transform:uppercase;margin-bottom:.45rem}.ac-slip strong{display:block;font-size:.95rem}.ac-slip p{font-size:.83rem;margin:.35rem 0 0;line-height:1.5}@media(max-width:600px){.ac-slip-grid{grid-template-columns:1fr}}
.ac-journey{margin:2rem 0}.ac-journey>h2{margin-bottom:.45rem}.ac-journey-intro{margin-bottom:1.2rem!important}.ac-journey-card{background:var(--surface);border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);box-shadow:var(--chip-md) var(--keyline);padding:1.2rem;margin:0 4px 1rem 0;scroll-margin-top:1rem}.ac-journey-step{display:inline-block;font-size:.7rem;font-weight:700;letter-spacing:.08em;color:var(--negative-strong);margin-bottom:.3rem}.ac-journey-card h3{font-family:var(--font-display);font-size:1.35rem;margin:.1rem 0 .55rem}.ac-journey-card>p{margin:.4rem 0 .9rem}.ac-journey-form{margin:1rem 0}.ac-journey-form>label{display:block;font-size:.83rem;font-weight:700;color:var(--ink);margin-bottom:.4rem}.ac-journey-input,.ac-journey-buttons{display:flex;flex-wrap:wrap;gap:.5rem}.ac-journey-input input{width:170px;max-width:100%;font:inherit;padding:.58rem .7rem;border:1px solid var(--ink-45);border-radius:var(--r-sm);background:var(--surface);color:var(--ink)}.ac-journey button{font:700 .8rem var(--font-body);background:var(--ink);color:var(--surface);border:var(--keyline-w) solid var(--keyline);border-radius:var(--r-sm);padding:.57rem .8rem;cursor:pointer}.ac-journey button:hover,.ac-journey button:focus-visible{background:var(--ink-strong)}.ac-journey button:disabled{opacity:.5;cursor:not-allowed}.ac-journey button[aria-pressed=true]{background:var(--positive-deep);border-color:var(--positive-deep)}.ac-journey-form p,.ac-journey-choice p{margin:.6rem 0 0!important;font-size:.85rem!important;color:var(--ink)!important}.ac-journey-choice{border-top:1px solid var(--rule);padding:1rem 0}.ac-journey-choice fieldset{border:0;margin:0 0 .7rem;padding:0}.ac-journey-choice legend{font-size:.9rem;font-weight:700;line-height:1.5;color:var(--ink);margin-bottom:.55rem}.ac-journey-choice label{display:block;padding:.5rem .6rem;border:1px solid var(--rule);border-radius:var(--r-sm);font-size:.83rem;line-height:1.5;color:var(--ink-70);margin:.35rem 0;cursor:pointer}.ac-journey-choice label:has(input:checked){background:var(--wash-2);border-color:var(--keyline)}.ac-journey-choice input{accent-color:var(--negative-strong);margin-right:.35rem}.ac-journey-choice [data-state=correct]{color:var(--positive-deep)!important}.ac-journey-choice [data-state=incorrect]{color:var(--negative-deep)!important}.ac-journey-help{border-top:1px solid var(--rule);padding-top:.7rem}.ac-journey-help summary{font-size:.82rem;font-weight:700;color:var(--info-strong);cursor:pointer}.ac-journey-help p{margin:.55rem 0 0!important;font-size:.84rem!important}.ac-journey-status{font-size:.83rem!important;margin:.6rem 0 0!important}.ac-journey-result{background:var(--wash);border:1px solid var(--rule);border-radius:var(--r-sm);padding:.9rem;margin:1rem 0}.ac-journey-result>strong{display:block;margin-bottom:.55rem}.ac-journey-result dl{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.55rem;margin:0}.ac-journey-result dl>div{border-bottom:1px solid var(--rule);padding-bottom:.45rem}.ac-journey-result dt{font-size:.73rem;color:var(--ink-70)}.ac-journey-result dd{font-size:1.1rem;font-weight:700;color:var(--ink);margin:.1rem 0 0;font-variant-numeric:tabular-nums}.ac-journey-result p{font-size:.82rem!important;margin:.7rem 0 0!important}.ac-journey [hidden]{display:none!important}@media(max-width:520px){.ac-journey-card{padding:1rem}.ac-journey-input input,.ac-journey-input button{width:100%}.ac-journey-buttons button{flex:1 1 100%}}
.ac-journey-optional>summary{cursor:pointer;list-style:none}.ac-journey-optional>summary::-webkit-details-marker{display:none}.ac-journey-optional>summary strong{display:block;font-family:var(--font-display);font-size:1.35rem;color:var(--ink)}.ac-journey-optional>summary small{display:block;font-size:.83rem;line-height:1.5;color:var(--ink-70);margin-top:.3rem}.ac-journey-optional-body{border-top:1px solid var(--rule);margin-top:1rem;padding-top:.5rem}.ac-journey-optional-body>p{font-size:.85rem!important;margin:.4rem 0 .8rem!important}