:root{
  --bg:#f4f7ff; --card:#ffffff; --ink:#1b2340; --muted:#6c7898;
  --primary:#3157d5; --primary-2:#6f52e5; --line:#dfe5f3; --soft:#eef3ff;
  --success:#158567; --success-soft:#eaf8f3; --danger:#d95c67; --danger-soft:#fff0f1;
  --warning:#e39c2f; --shadow:0 18px 50px rgba(42,63,120,.12);
  --radius:24px;
}
*{box-sizing:border-box}html,body{margin:0;min-height:100%;font-family:Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;color:var(--ink);background:linear-gradient(180deg,#f7f9ff 0,#f4f7ff 55%,#eef3ff 100%)}
button,input{font:inherit}.topbar{height:82px;display:flex;align-items:center;justify-content:space-between;padding:0 40px;border-bottom:1px solid rgba(212,221,242,.8);background:rgba(255,255,255,.82);backdrop-filter:blur(18px);position:sticky;top:0;z-index:20}.brand{display:flex;align-items:center;gap:12px;cursor:pointer}.brand-mark{width:42px;height:42px;border-radius:14px;background:linear-gradient(135deg,var(--primary),var(--primary-2));color:white;display:grid;place-items:center;font-size:22px;font-weight:900;box-shadow:0 8px 22px rgba(49,87,213,.28)}.brand strong,.brand span{display:block}.brand strong{font-size:16px}.brand span{font-size:12px;color:var(--muted);margin-top:2px}.page-shell{width:min(1180px,calc(100% - 40px));margin:34px auto 70px}.screen{display:none}.screen.active{display:block}.ghost-btn,.secondary-btn,.outline-btn,.primary-btn{border:0;border-radius:14px;padding:12px 18px;font-weight:800;cursor:pointer;transition:.2s ease}.ghost-btn{background:#f2f5fb;color:var(--ink)}.secondary-btn{background:#eef2fb;color:var(--ink)}.outline-btn{background:white;border:1.5px solid #cfd8ee;color:var(--primary)}.primary-btn{background:linear-gradient(135deg,var(--primary),#5f58df);color:white;box-shadow:0 8px 20px rgba(49,87,213,.22)}button:hover{transform:translateY(-1px)}button:disabled{opacity:.45;cursor:not-allowed;transform:none}.hero-card{display:grid;grid-template-columns:1.2fr .8fr;min-height:330px;border-radius:32px;padding:46px;background:linear-gradient(135deg,#172552 0%,#2f4fbc 58%,#745be4 100%);color:white;overflow:hidden;position:relative;box-shadow:var(--shadow)}.hero-card:before,.hero-card:after{content:"";position:absolute;border-radius:50%;background:rgba(255,255,255,.08)}.hero-card:before{width:320px;height:320px;right:-80px;top:-120px}.hero-card:after{width:210px;height:210px;right:200px;bottom:-140px}.eyebrow{font-size:12px;letter-spacing:.14em;font-weight:900;text-transform:uppercase;color:#89a1f5}.hero-card .eyebrow{color:#b8c7ff}.hero-copy{align-self:center;position:relative;z-index:2}.hero-copy h1{font-size:clamp(36px,5vw,58px);line-height:1.03;margin:12px 0 16px;letter-spacing:-.04em}.hero-copy h1 span{color:#cdd7ff}.hero-copy p{max-width:680px;color:#e0e6ff;line-height:1.7;font-size:16px}.hero-visual{display:grid;place-items:center;position:relative;z-index:2}.mini-paper{width:260px;min-height:250px;background:white;border-radius:26px;color:var(--ink);padding:28px 34px;transform:rotate(3deg);box-shadow:0 28px 55px rgba(10,18,60,.25);background-image:linear-gradient(#e7edf9 1px,transparent 1px),linear-gradient(90deg,#e7edf9 1px,transparent 1px);background-size:28px 28px}.mini-carry{text-align:right;padding-right:47px;color:var(--primary);font-weight:900;font-size:18px;height:28px}.mini-line{display:grid;grid-template-columns:30px repeat(3,1fr);align-items:center;text-align:center;font-size:34px;font-weight:800;margin:6px 0}.mini-line strong{font-size:28px}.mini-rule{height:4px;background:var(--ink);border-radius:9px;margin:8px 0}.mini-answer i{font-style:normal;border:2px solid #9db0ef;border-radius:10px;background:#edf2ff;font-size:28px;padding:3px 0}.config-panel{background:white;border:1px solid #e1e7f4;border-radius:26px;padding:28px;margin-top:22px;box-shadow:0 10px 26px rgba(60,79,130,.05)}.section-heading{display:flex;gap:14px;align-items:flex-start;margin-bottom:22px}.section-heading>div:first-child span{width:34px;height:34px;border-radius:11px;background:var(--soft);color:var(--primary);font-weight:900;display:grid;place-items:center}.section-heading h2{font-size:20px;margin:0 0 5px}.section-heading p{color:var(--muted);margin:0;font-size:14px}.section-heading.compact{margin-bottom:16px}.choice-grid{display:grid;gap:14px}.mode-grid{grid-template-columns:repeat(3,1fr)}.operation-grid{grid-template-columns:repeat(4,1fr)}.choice-card,.op-card{background:#fbfcff;border:2px solid #e3e8f5;border-radius:20px;text-align:left;padding:20px;cursor:pointer;color:var(--ink)}.choice-card.selected,.op-card.selected{border-color:var(--primary);background:#f2f5ff;box-shadow:0 0 0 4px rgba(49,87,213,.07)}.choice-icon{width:40px;height:40px;border-radius:14px;background:#edf2ff;color:var(--primary);display:grid;place-items:center;font-weight:900;margin-bottom:14px}.choice-card strong,.choice-card small{display:block}.choice-card strong{font-size:17px}.choice-card small{color:var(--muted);line-height:1.5;margin-top:4px}.op-card{text-align:center;padding:18px 10px}.op-card b{display:grid;place-items:center;width:48px;height:48px;border-radius:16px;background:#eef2fb;margin:0 auto 9px;font-size:28px;color:var(--primary)}.op-card span{font-weight:800}.split-config{display:grid;grid-template-columns:1fr 1fr;gap:32px}.segmented{display:flex;gap:8px;background:#f3f6fb;padding:7px;border-radius:16px}.segmented button{flex:1;border:0;background:transparent;padding:12px 10px;border-radius:11px;font-weight:800;color:var(--muted);cursor:pointer}.segmented button.selected{background:white;color:var(--primary);box-shadow:0 4px 14px rgba(50,70,120,.1)}.start-bar{margin-top:22px;border-radius:24px;background:#172552;color:white;padding:22px 24px;display:flex;align-items:center;justify-content:space-between;gap:20px}.start-bar strong,.start-bar span{display:block}.start-bar span{color:#aebce8;font-size:13px;margin-top:4px}.primary-btn.large{padding:16px 24px;font-size:15px}.exercise-top{display:flex;align-items:end;justify-content:space-between;gap:20px}.exercise-top h2{margin:6px 0 0;font-size:30px}.exercise-meta{display:flex;gap:10px;align-items:center}.timer-card{padding:10px 16px;background:white;border:1px solid var(--line);border-radius:14px;text-align:center}.timer-card small,.timer-card strong{display:block}.timer-card small{font-size:10px;color:var(--muted);text-transform:uppercase;font-weight:800}.timer-card strong{font-size:16px;margin-top:2px}.progress-track{height:8px;background:#dce4f7;border-radius:99px;overflow:hidden;margin:18px 0 12px}.progress-track>div{height:100%;width:20%;background:linear-gradient(90deg,var(--primary),var(--primary-2));transition:width .25s}.question-dots{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:22px}.qdot{width:36px;height:36px;border-radius:11px;background:white;border:1.5px solid var(--line);display:grid;place-items:center;font-weight:800;color:var(--muted);cursor:pointer}.qdot.current{border-color:var(--primary);color:var(--primary);background:#edf2ff}.qdot.done{background:#edf8f4;border-color:#b9e5d6;color:var(--success)}.qdot.has-data:after{content:"";width:6px;height:6px;background:var(--primary);border-radius:50%;position:absolute;margin:24px 0 0 24px}.qdot{position:relative}.exercise-layout{display:grid;grid-template-columns:280px 1fr;gap:22px}.instruction-card{background:white;border:1px solid var(--line);border-radius:24px;padding:24px;height:max-content;box-shadow:0 10px 26px rgba(60,79,130,.05)}.instruction-badge{width:56px;height:56px;display:grid;place-items:center;background:var(--soft);color:var(--primary);border-radius:18px;font-size:32px;font-weight:900}.instruction-card h3{font-size:21px;margin:18px 0 9px}.instruction-card p{color:var(--muted);line-height:1.6;font-size:14px}.tip-box{background:#f7f9ff;border-radius:16px;padding:14px;margin-top:18px}.tip-box strong,.tip-box span{display:block}.tip-box strong{font-size:12px;color:var(--primary);text-transform:uppercase;letter-spacing:.08em}.tip-box span{font-size:13px;color:var(--muted);line-height:1.5;margin-top:5px}.workspace-card{background:white;border:1px solid var(--line);border-radius:28px;padding:22px;min-height:520px;box-shadow:0 12px 32px rgba(60,79,130,.06)}.paper-labels{display:flex;justify-content:space-between;color:var(--muted);font-size:12px;font-weight:800;padding:2px 4px 12px}.arithmetic-board{min-height:420px;border-radius:22px;border:1px solid #dbe4f3;background-color:#fbfdff;background-image:linear-gradient(#eaf0fb 1px,transparent 1px),linear-gradient(90deg,#eaf0fb 1px,transparent 1px);background-size:38px 38px;display:flex;justify-content:center;align-items:center;padding:36px;overflow:auto}.math-stack{display:flex;flex-direction:column;gap:8px;min-width:max-content}.math-row{display:grid;grid-auto-flow:column;grid-auto-columns:58px;align-items:center;justify-content:end}.math-row.helper{min-height:44px}.math-row.helper .helper-cell{display:grid;place-items:center;min-height:44px}.math-row.helper .helper-input{width:36px;height:34px;border:2px dashed #94a9df;border-radius:9px;background:#f7f9ff;color:var(--primary);text-align:center;font-size:18px;font-weight:900;outline:none}.math-row.helper .helper-input:focus{border-style:solid;box-shadow:0 0 0 4px rgba(49,87,213,.1)}.math-cell{height:58px;display:grid;place-items:center;font-size:38px;font-weight:900}.math-cell.borrowed-digit{position:relative}.math-cell.borrowed-digit .original-crossed{position:relative;display:inline-block;line-height:1}.math-cell.borrowed-digit .original-crossed:after{content:'';position:absolute;left:-6px;right:-6px;top:50%;height:4px;background:#d94a52;border-radius:99px;transform:rotate(-58deg)}.operator-cell{font-size:28px;color:var(--primary)}.math-rule{height:4px;background:var(--ink);border-radius:99px;margin:2px 0 6px}.answer-row .digit-input,.partial-row .digit-input,.division-input{width:48px;height:54px;border:2px solid #9fb0dc;border-radius:12px;background:#fff;color:var(--ink);text-align:center;font-size:30px;font-weight:900;outline:none}.digit-input:focus,.division-input:focus{border-color:var(--primary);box-shadow:0 0 0 5px rgba(49,87,213,.11)}.digit-input.correct,.helper-input.correct,.division-input.correct{border-color:var(--success);background:var(--success-soft)}.digit-input.wrong,.helper-input.wrong,.division-input.wrong{border-color:var(--danger);background:var(--danger-soft)}.partial-label{font-size:12px;color:var(--muted);font-weight:800;text-align:right;margin:4px 0 -2px}.partial-row{opacity:.95}.school-division{--division-cell:54px;min-width:max-content;display:grid;grid-template-columns:auto minmax(170px,auto);grid-template-rows:auto auto;align-items:start;padding:10px 18px 18px}.school-dividend{grid-column:1;grid-row:1;display:grid;grid-auto-flow:column;grid-auto-columns:var(--division-cell);align-items:center;margin-left:20px}.school-number-cell{width:var(--division-cell);height:58px;display:grid;place-items:center;font-size:38px;font-weight:900}.school-key-head{grid-column:2;grid-row:1;border-left:4px solid var(--ink);height:58px}.school-divisor{height:58px;display:flex;align-items:center;padding-left:20px;font-size:38px;font-weight:900}.school-key-body{grid-column:2;grid-row:2;border-left:4px solid var(--ink);border-top:4px solid var(--ink);min-height:64px;align-self:start}.school-quotient{display:flex;gap:7px;padding:10px 14px 0 18px;min-height:64px}.school-division-input{width:46px;height:50px;border:2px solid #9fb0dc;border-radius:10px;background:rgba(255,255,255,.94);color:var(--ink);text-align:center;font-size:29px;font-weight:900;outline:none;z-index:2}.school-division-input:focus{border-color:var(--primary);box-shadow:0 0 0 5px rgba(49,87,213,.11)}.school-division-input.correct{border-color:var(--success);background:var(--success-soft)}.school-division-input.wrong{border-color:var(--danger);background:var(--danger-soft)}.school-work{grid-column:1;grid-row:2;width:calc(var(--dvd-cols)*var(--division-cell));margin-left:20px}.school-step{display:grid}.school-work-row,.school-sub-rule-row{display:grid;grid-template-columns:repeat(var(--dvd-cols),var(--division-cell));min-height:55px;position:relative;align-items:center;overflow:visible}.school-work-row .school-division-input{justify-self:center}.school-product-row .school-division-input{margin-top:1px}.school-minus{position:absolute;align-self:center;justify-self:start;transform:translateX(-20px);font-size:28px;font-weight:800;color:var(--ink)}.school-sub-rule-row{min-height:8px}.school-sub-rule{height:3px;background:var(--ink);border-radius:9px;align-self:start;margin:0 5px}.school-down-arrow{justify-self:center;align-self:start;transform:translateY(-28px);font-size:28px;line-height:1;color:var(--primary);font-weight:900;pointer-events:none;position:relative;z-index:8;text-shadow:0 0 0 transparent}.school-work-row.next{margin-top:8px}.school-remainder-row{margin-top:4px}.school-remainder-row .school-division-input{border-style:solid}.question-feedback{margin-top:16px;padding:14px 16px;border-radius:15px;font-weight:700}.question-feedback.success{background:var(--success-soft);color:var(--success)}.question-feedback.danger{background:var(--danger-soft);color:#b8424e}.exercise-actions{display:grid;grid-template-columns:1fr 1fr 1fr;align-items:center;margin-top:20px}.exercise-actions .center-actions{text-align:center}.exercise-actions>#next-btn{justify-self:end}.hidden{display:none!important}.results-hero{display:grid;grid-template-columns:180px 1fr;align-items:center;gap:32px;background:white;border:1px solid var(--line);border-radius:30px;padding:32px;box-shadow:var(--shadow)}.score-ring{--p:0%;width:160px;height:160px;border-radius:50%;display:grid;place-items:center;background:conic-gradient(var(--primary) var(--p),#e6ebf6 0)}.score-ring:after{content:"";width:122px;height:122px;background:white;border-radius:50%;position:absolute}.score-ring{position:relative}.score-ring>div{position:relative;z-index:1;text-align:center}.score-ring strong,.score-ring span{display:block}.score-ring strong{font-size:34px}.score-ring span{font-size:11px;color:var(--muted);font-weight:800}.results-hero h1{font-size:34px;margin:8px 0 8px}.results-hero p{margin:0;color:var(--muted);line-height:1.6}.stats-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:20px 0}.stat-card{background:white;border:1px solid var(--line);border-radius:20px;padding:20px;display:flex;gap:14px;align-items:center}.stat-card>span{width:44px;height:44px;border-radius:14px;display:grid;place-items:center;font-weight:900;font-size:20px}.stat-card.success>span{background:var(--success-soft);color:var(--success)}.stat-card.danger>span{background:var(--danger-soft);color:var(--danger)}.stat-card.neutral>span{background:var(--soft);color:var(--primary)}.stat-card strong,.stat-card small{display:block}.stat-card strong{font-size:28px}.stat-card small{color:var(--muted);margin-top:2px}.review-panel{background:white;border:1px solid var(--line);border-radius:28px;padding:26px}.review-heading{display:flex;justify-content:space-between;align-items:center;gap:20px}.review-heading h2{margin:0 0 5px}.review-heading p{margin:0;color:var(--muted)}.review-list{display:grid;gap:12px;margin-top:22px}.review-item{border:1px solid var(--line);border-radius:18px;overflow:hidden}.review-summary{display:grid;grid-template-columns:48px 1fr auto;gap:14px;align-items:center;padding:16px;cursor:pointer}.review-status{width:42px;height:42px;border-radius:13px;display:grid;place-items:center;font-weight:900}.review-item.correct .review-status{background:var(--success-soft);color:var(--success)}.review-item.wrong .review-status{background:var(--danger-soft);color:var(--danger)}.review-summary strong,.review-summary span{display:block}.review-summary span{color:var(--muted);font-size:13px;margin-top:3px}.review-chip{font-size:12px;font-weight:900;padding:7px 10px;border-radius:10px}.review-item.correct .review-chip{background:var(--success-soft);color:var(--success)}.review-item.wrong .review-chip{background:var(--danger-soft);color:var(--danger)}.review-detail{display:none;padding:0 16px 16px 78px}.review-item.open .review-detail{display:block}.review-detail-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px}.review-detail-box{background:#f7f9fd;border-radius:14px;padding:12px}.review-detail-box small,.review-detail-box strong{display:block}.review-detail-box small{color:var(--muted);font-size:11px;text-transform:uppercase;font-weight:800}.review-detail-box strong{margin-top:4px}dialog{border:0;padding:0;background:transparent}dialog::backdrop{background:rgba(19,30,66,.44);backdrop-filter:blur(4px)}.dialog-card{width:min(420px,calc(100vw - 32px));background:white;border-radius:24px;padding:28px;text-align:center}.dialog-icon{width:54px;height:54px;border-radius:18px;background:var(--soft);color:var(--primary);display:grid;place-items:center;font-size:28px;font-weight:900;margin:0 auto}.dialog-card h3{font-size:22px;margin:16px 0 8px}.dialog-card p{color:var(--muted);line-height:1.5}.dialog-actions{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:20px}
@media(max-width:900px){.topbar{padding:0 20px}.page-shell{width:min(100% - 24px,1180px);margin-top:18px}.hero-card{grid-template-columns:1fr;padding:32px}.hero-visual{display:none}.mode-grid,.operation-grid{grid-template-columns:repeat(2,1fr)}.split-config{grid-template-columns:1fr}.exercise-layout{grid-template-columns:1fr}.instruction-card{display:grid;grid-template-columns:auto 1fr;column-gap:14px}.instruction-card h3{margin:2px 0 5px}.instruction-card p{margin:0}.tip-box{grid-column:1/-1}.stats-grid{grid-template-columns:1fr}.results-hero{grid-template-columns:1fr;text-align:center}.score-ring{margin:auto}}
@media(max-width:620px){.topbar{height:72px}.brand span{display:none}.topbar-actions{display:none}.page-shell{width:calc(100% - 18px)}.hero-card{padding:26px 22px;border-radius:24px}.hero-copy h1{font-size:38px}.config-panel{padding:20px;border-radius:20px}.mode-grid,.operation-grid{grid-template-columns:1fr 1fr}.choice-card{padding:16px}.choice-card small{font-size:12px}.split-config{gap:20px}.start-bar{align-items:stretch;flex-direction:column}.primary-btn.large{width:100%}.exercise-top h2{font-size:24px}.exercise-layout{gap:14px}.instruction-card{padding:18px}.workspace-card{padding:10px;min-height:470px}.arithmetic-board{padding:24px 10px;min-height:390px}.math-row{grid-auto-columns:50px}.math-cell{font-size:32px}.answer-row .digit-input,.partial-row .digit-input{width:43px;height:50px;font-size:27px}.exercise-actions{grid-template-columns:auto 1fr auto;gap:8px}.exercise-actions button{padding:11px 12px;font-size:13px}.results-hero{padding:24px 18px}.results-hero h1{font-size:28px}.review-panel{padding:18px}.review-heading{align-items:flex-start;flex-direction:column}.review-detail{padding:0 12px 12px}.review-detail-grid{grid-template-columns:1fr}.review-summary{grid-template-columns:42px 1fr auto;gap:10px}.school-division{--division-cell:48px;padding:6px 5px 12px}.school-number-cell{height:52px;font-size:33px}.school-division{grid-template-columns:auto minmax(145px,auto)}.school-key-head{height:52px}.school-divisor{height:52px;font-size:33px;padding-left:15px}.school-division-input{width:41px;height:46px;font-size:26px}.school-quotient{padding:9px 10px 0 14px}.school-work-row,.school-sub-rule-row{min-height:51px}}

/* v3: dica, resto no resultado e estados de correção */
.tip-box-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:8px}.tip-box-head strong{margin:0}.hint-btn{border:1.5px solid #b9c7eb;background:#fff;color:var(--primary);border-radius:10px;padding:7px 10px;font-size:12px;font-weight:900;cursor:pointer}.hint-btn:disabled{cursor:default;opacity:1;background:#fff7df;color:#9b6b13;border-color:#ecd18e}.tip-box.used{background:#fff9e9;border-color:#f0d998}.tip-box.used #hint-text{color:#76551d}.school-result-comma{align-self:end;font-size:34px;font-weight:900;line-height:1;padding:0 0 7px 0;color:var(--ink)}.question-feedback.hinted{background:#fff8e4;color:#8a6417}.review-item.hinted .review-status{background:#fff3cf;color:#9a6a00}.review-item.hinted .review-chip{background:#fff3cf;color:#8a6417}.review-item.hinted{border-color:#f0dc9b}


/* v0.4.0 — resolução progressiva */
.app-version{display:inline-flex;align-items:center;justify-content:center;padding:5px 9px;border:1px solid #d9e1f4;border-radius:999px;background:#f7f9ff;color:#60709a;font-size:11px;font-weight:900;letter-spacing:.04em;white-space:nowrap}.app-version-fixed{position:fixed;right:14px;bottom:12px;z-index:50;box-shadow:0 4px 14px rgba(40,58,104,.08)}
.progressive-hidden{visibility:hidden!important;opacity:0!important;pointer-events:none!important}.progressive-structure-hidden{display:none!important}
.school-division-input,.digit-input,.helper-input{transition:opacity .14s ease,transform .14s ease,box-shadow .14s ease}
.school-division-input:not(.progressive-hidden),.digit-input:not(.progressive-hidden),.helper-input:not(.progressive-hidden){animation:fieldReveal .16s ease-out}
@keyframes fieldReveal{from{opacity:0;transform:scale(.88)}to{opacity:1;transform:scale(1)}}
@media(max-width:700px){.app-version{font-size:10px;padding:4px 7px}}

/* v0.5.0 — seleção do trecho inicial da divisão */
.division-select-digit{
  appearance:none;
  border:0;
  background:transparent;
  color:var(--ink);
  padding:0;
  margin:0;
  cursor:pointer;
  border-radius:10px;
  transition:background .14s ease,color .14s ease,box-shadow .14s ease,transform .14s ease;
}
.division-select-digit:hover:not(:disabled),
.division-select-digit:focus-visible{
  background:#eef3ff;
  box-shadow:0 0 0 3px rgba(49,87,213,.10);
  outline:none;
}
.division-select-digit.selected{
  background:#e7edff;
  color:var(--primary);
  box-shadow:inset 0 -3px 0 #8ca4ef;
}
.division-select-digit.selection-complete{
  background:#dfe8ff;
  color:#183aaf;
  box-shadow:inset 0 -3px 0 var(--primary),0 0 0 2px rgba(49,87,213,.09);
}
.division-select-digit.next-selectable{
  animation:divisionNextDigitPulse 1.1s ease-in-out infinite;
}
.division-select-digit:disabled{opacity:1;cursor:default}
@keyframes divisionNextDigitPulse{
  0%,100%{box-shadow:0 0 0 0 rgba(49,87,213,0)}
  50%{box-shadow:0 0 0 5px rgba(49,87,213,.10)}
}