/* Mathverse CAT — itineraris de derivació i integració, mòbil primer */
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.calc-homebanner h2{font-size:clamp(23px,4vw,36px);margin:8px 0 12px}.calc-homebanner p{max-width:850px;color:#cbd8ec}.calc-curriculum{font-size:.9rem;padding:14px 20px}
.calc-header{padding:20px 0}.calc-header h1{margin:9px 0 6px;font-size:clamp(31px,5vw,52px)}.calc-header p{color:#c9d5eb;max-width:750px}.calc-header .eyebrow{display:block;margin-top:14px}.calc-progress{max-width:460px;color:#e1e9fa;margin-top:14px}.calc-progress .meter{margin-top:10px}
.calc-shell{display:grid;grid-template-columns:minmax(205px,265px) minmax(0,1fr);gap:18px;align-items:start}
.calc-catalog,.calc-card{border-radius:18px;border:1px solid rgba(146,182,238,.22);background:rgba(11,19,47,.92);box-shadow:0 12px 50px #070c203d}.calc-catalog{padding:13px;max-height:min(80vh,900px);overflow:auto;position:sticky;top:76px}.calc-catalog h3{font-size:15px;margin:8px 8px 14px;color:#eef5ff}
.calc-chapter{width:100%;display:flex;align-items:center;gap:12px;text-align:left;background:transparent;color:#d6e4ff;border:1px solid transparent;border-radius:12px;padding:9px 10px;cursor:pointer;margin-bottom:4px;min-height:55px}.calc-chapter>span:first-child{display:grid;place-items:center;width:31px;height:31px;flex:none;background:#1d3153;border-radius:8px;color:#9eeede;font-weight:750;font-size:12px}.calc-chapter strong{display:block;font-size:13px}.calc-chapter small{display:block;font-size:11px;color:#9fb3ce;margin-top:3px}.calc-chapter.selected{background:#1b3c5c;border-color:#74d7e5;color:white}.calc-chapter:hover{background:#234565}
.calc-main{display:grid;gap:17px;min-width:0}.calc-card{padding:clamp(16px,3vw,25px);overflow:hidden}.calc-card h2{font-size:clamp(24px,3vw,34px);margin:7px 0}.calc-card h3{margin:8px 0 12px}.calc-card>p{color:#d2e1f6;line-height:1.55}
.calc-formula{background:rgba(65,86,151,.25);border:1px solid #476ca2;color:#fff0c2;border-radius:12px;font-weight:650;padding:18px;margin:15px 0;font-size:clamp(16px,2.1vw,22px);overflow-wrap:anywhere}.calc-tabs{display:flex;gap:7px;margin:23px 0 12px}.calc-tabs button{flex:1;padding:12px 9px;border-radius:10px;border:1px solid #3d5487;background:#172348;color:#bdceeb;cursor:pointer;min-height:48px}.calc-tabs button.active{background:#1e6d80;color:white;border-color:#77dfe1}
.calc-tutorial,.calc-practice{background:#0c1936;border-radius:13px;padding:17px;border:1px solid #293d66}.calc-step{font-size:clamp(17px,2.3vw,21px);font-weight:600;line-height:1.58;background:#182f57;border-radius:12px;padding:22px 16px;min-height:112px;color:#f3f7ff}.calc-dots{display:flex;gap:8px;justify-content:center;align-items:center;margin:15px 0}.calc-dots button{width:15px;height:15px;border:1px solid #5b79aa;border-radius:100%;background:#233f68;cursor:pointer}.calc-dots button.active{background:#94eeec;border-color:#b7ffff}.calc-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:16px}.calc-actions .btn{min-height:43px}.calc-quiz{padding:15px;border-top:1px solid #36527c;margin-top:20px}.calc-quiz p{font-size:16px}.calc-practice p{line-height:1.6}.calc-equation{font-weight:800;color:#86eeea;font-size:clamp(19px,3vw,25px);overflow-wrap:anywhere}.calc-editor{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:15px 0}.calc-editor label{font-weight:700}.calc-editor input{min-width:150px;flex:1;background:#101f40;color:#fff;border:1px solid #6382bb;border-radius:11px;min-height:48px;font:inherit;padding:12px}.calc-editor input:focus{outline:2px solid #8eeae6}.calc-message{border-radius:10px;padding:12px;line-height:1.45}.calc-message.ok{color:#bcfce0;background:rgba(11,103,78,.32)}.calc-message.not-ok{color:#ffd2bf;background:rgba(146,65,63,.24)}.calc-victory{margin-top:20px;border:1px solid #73dfd3;border-radius:13px;background:#123e47;padding:16px}.calc-victory h3{color:#a8f6df}
.calc-graph{margin-top:13px}.calc-legend{display:flex;flex-wrap:wrap;gap:15px;color:#d8e5fd;font-size:12px;margin-bottom:13px}.calc-legend span{display:flex;align-items:center;gap:7px}.calc-legend i{display:inline-block;width:16px;height:4px;border-radius:9px}.calc-graph svg{width:100%;height:auto;border:1px solid #394e78;border-radius:13px}.calc-graph label{display:block;margin:14px 0 10px;color:#e3efff}.calc-graph input[type=range]{display:block;width:100%;margin-top:9px;accent-color:#5cdbd1;min-height:29px}.calc-coordinates{color:#e7faff;background:#193356;border-radius:10px;padding:11px;font-size:13px}
@media(max-width:850px){.calc-shell{grid-template-columns:1fr}.calc-catalog{position:static;display:flex;gap:8px;overflow-x:auto;overflow-y:hidden;max-height:none;padding:10px;align-items:stretch}.calc-catalog h3{display:none}.calc-chapter{min-width:180px;max-width:220px;flex:none;margin:0}.calc-main{gap:12px}.calc-header{padding:12px 0}}
@media(max-width:430px){.calc-card{padding:12px}.calc-tabs{flex-wrap:wrap}.calc-editor .btn{width:100%}.calc-step{padding:14px}.calc-chapter{min-width:155px}.site-credit{font-size:.78rem}}
@media(prefers-reduced-motion:reduce){.calc-chapter,.calc-tabs button{transition:none}}

/* 7.1: derivada f'(x) independent de la recta tangent: reforç visual */
.calc-explain{padding:12px 14px;margin:11px 0;border-radius:11px;color:#e5efff;font-size:13px;line-height:1.55;background:rgba(47,81,126,.32);border:1px solid rgba(143,181,228,.22)}
.calc-explain strong{color:#fff}
.calc-live-values{display:flex;flex-wrap:wrap;gap:8px 16px;justify-content:space-between}
.calc-live-values span{display:inline-flex;flex-wrap:wrap;gap:5px;align-items:center}
.calc-live-slope strong{color:#f5bd72}
.calc-live-equation{margin-top:11px;border-top:1px solid rgba(198,224,255,.24);padding-top:11px;line-height:1.6;overflow-wrap:anywhere}
.calc-live-equation strong{color:#ffe188}
@media(max-width:430px){.calc-live-values{flex-direction:column;gap:6px}}