/* A clear class → subject → lesson path, with the same navigation on phones. */
.study-intro{max-width:880px;margin:0 0 26px}.study-intro h1{font-size:clamp(2rem,4.5vw,3rem);max-width:750px;line-height:1.16}.study-intro p{font-size:1.05rem;max-width:740px;line-height:1.7}.study-sequence{display:flex;flex-wrap:wrap;gap:12px;margin:22px 0}.study-sequence span{display:flex;align-items:center;gap:9px;font-size:.95rem}.study-sequence b{display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:#e8e0f2;color:#49355f}.class-picker{padding:24px;background:white;border:1px solid var(--line);border-radius:20px}.class-picker h2{font-size:1.25rem;margin-bottom:7px}.class-picker p{font-size:.92rem;margin-bottom:15px}.class-picker .grade-grid{display:flex;flex-wrap:wrap;gap:10px}.class-picker .grade{height:auto;min-height:48px;min-width:64px;padding:10px 17px;font-size:1rem}.study-start{display:flex;gap:24px;align-items:center;justify-content:space-between;padding:22px 25px;margin-top:20px;border:1px solid #dfd4ae;background:#fff4d8;border-radius:20px}.study-start h2{font-size:1.2rem;margin-bottom:7px}.study-start p{margin:0;font-size:.95rem}.study-start>div{min-width:0}.study-start .button-primary{white-space:normal;flex-shrink:0;font-size:.94rem;min-height:48px}.catalog{margin-top:30px}.catalog .section-title{align-items:center;flex-wrap:wrap}.catalog .section-title p{font-size:1rem}.catalog .section-title>span{font-size:.9rem}.subject-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.subject-card{text-align:left;padding:23px;display:flex;align-items:flex-start;gap:17px;background:white;border:1px solid var(--line);border-radius:20px;color:var(--ink)}.subject-card:hover{border-color:#8b74a2;background:#f7f3fc}.subject-card>span:first-child{display:grid;place-items:center;flex-shrink:0;width:48px;height:48px;border-radius:14px;background:#e8e0f2;font-size:1.4rem}.subject-card strong{display:block;font-size:1.15rem;line-height:1.4;margin-bottom:6px}.subject-card small{display:block;color:var(--muted);font-size:.95rem;line-height:1.65}.subject-card em{display:block;font-style:normal;font-weight:700;color:#5e4579;margin-top:13px;font-size:.9rem}.catalog-back{margin-bottom:20px;min-height:44px}.catalog .activity-card{min-height:210px}.catalog .activity-card h3{font-size:1.13rem}.catalog .activity-card p{font-size:.96rem;max-width:none}.catalog .card-area{font-size:.8rem;text-transform:none;letter-spacing:0}.catalog .card-bottom{font-size:.88rem}.catalog .activity-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-card-number{font-size:.8rem;font-weight:bold;color:#685677}.lesson-card-label{margin-bottom:12px;font-size:.84rem;color:#5e4579}.catalog-empty{padding:22px;background:white;border:1px solid var(--line);border-radius:16px}.catalog-empty h3{font-size:1.2rem}.catalog-empty p{font-size:1rem}.study-help{padding:19px 22px;margin-top:22px;background:#eee9f5;border-radius:16px;font-size:.96rem;line-height:1.7}.study-help p{margin:0}.geometry-path{padding:20px}.geometry-path h3{font-size:1.2rem}.geometry-all-topics>summary{font-size:1rem}.geometry-topic-groups button{font-size:.96rem;line-height:1.5}.geometry-topic-groups h4{font-size:1.05rem}.activity-dialog{width:min(860px,96vw)}.dialog-top .eyebrow{font-size:.8rem;letter-spacing:.04em}.activity-dialog h2{font-size:clamp(1.35rem,3vw,1.85rem);line-height:1.35}.activity-toolbar{margin-bottom:18px;gap:10px}.activity-toolbar label,.activity-toolbar select,.listen-button{font-size:.95rem}.activity-toolbar select{max-width:260px;min-height:44px}.listen-button{min-height:44px}.main-nav a,.adult-link{min-height:44px;display:inline-flex;align-items:center}.site-header{height:auto;min-height:94px;flex-wrap:wrap;row-gap:10px;padding-top:15px;padding-bottom:15px}.main-nav{display:flex}.site-footer{font-size:.88rem}.button-primary,.button-secondary{min-height:44px;white-space:normal}.study-intro,.class-picker,.study-start,.subject-grid,.subject-card,.catalog,.activity-card,.geometry-path{min-width:0;overflow-wrap:break-word}
.activity-dialog:has(.learning-exercises[hidden]) .activity-toolbar label[for="activity-support"],.activity-dialog:has(.learning-exercises[hidden]) #activity-support{display:none}
#activity-count{display:flex;align-items:center;gap:12px;flex-wrap:wrap}#activity-count a{display:inline-flex;align-items:center;min-height:44px;color:#5a417d;font-weight:700;text-underline-offset:4px}.class-picker{scroll-margin-top:20px}
@media(max-width:480px){.site-header .main-nav{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));width:100%;min-width:0;gap:3px}.site-header .main-nav a{justify-content:center;min-width:0;padding:10px 4px;font-size:.88rem;white-space:normal;text-align:center}}
@media(max-width:760px){.site-header{height:auto;gap:10px}.brand>span{font-size:1.65rem}.brand small{display:none}.main-nav{display:flex;order:3;flex-basis:100%;gap:5px;justify-content:flex-start}.main-nav a{padding:10px 13px;font-size:.95rem}.header-actions{margin-left:auto}.adult-link{font-size:.85rem}.icon-button{width:44px;height:44px}.study-intro p{font-size:1rem}.study-start{flex-direction:column;align-items:stretch;gap:16px}.class-picker{padding:20px}.study-start .button-primary{align-self:flex-start}.catalog .section-title>span{display:block}.subject-grid,.catalog .activity-grid{grid-template-columns:minmax(0,1fr)}.subject-card{padding:20px}.study-sequence{gap:10px;flex-direction:column}.catalog .activity-card{min-height:0}.activity-toolbar{flex-wrap:wrap}.activity-toolbar label{width:auto}.activity-toolbar select{max-width:100%;flex:1 1 160px;min-width:0}.listen-button{margin-left:0}.geometry-path{padding:16px}.site-footer{line-height:1.7}.class-picker .grade{flex:1;min-width:44px;padding:10px 8px}.class-picker .grade-grid{gap:7px}.activity-dialog{padding:18px 15px}.header-actions{gap:7px}}