:root{
  --bg:#f3f1ec;
  --paper:#fff;
  --paper-soft:#faf9f5;
  --text:#171717;
  --muted:#747474;
  --line:rgba(23,23,23,.16);
  --line-strong:rgba(23,23,23,.32);
  --black:#171717;
  --green:#357b45;
  --green-soft:#edf5ee;
  --red:#b94a43;
  --red-soft:#faeeee;
  --note:#f3f0e7;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;color:var(--text);background:var(--bg);font-family:Meiryo,"Hiragino Kaku Gothic ProN","Hiragino Sans","Noto Sans JP",sans-serif;font-size:16px;font-weight:400;line-height:1.75;letter-spacing:.015em}
button,input{font:inherit}button{touch-action:manipulation}.hidden{display:none!important}.view{display:none}.view.active{display:block}
.top-header{background:rgba(243,241,236,.96);border-bottom:1px solid rgba(23,23,23,.08);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px)}
.top-header-inner{max-width:960px;margin:0 auto;padding:17px 18px 13px;display:flex;align-items:center}
.brand-title{font-size:13px;font-weight:800;letter-spacing:.22em;line-height:1.2}
.brand-sub{font-size:.75rem;color:var(--muted);margin-top:5px;font-weight:600;letter-spacing:.08em}
.main-nav{border-top:1px solid rgba(23,23,23,.04);border-bottom:1px solid var(--line)}
.main-nav-inner{max-width:960px;margin:0 auto;padding:8px 18px;display:flex;justify-content:space-between;gap:16px;align-items:center;font-size:.75rem;color:var(--muted);letter-spacing:.08em}
.nav-current{font-weight:800;color:var(--text)}
.page-wrap{max-width:960px;margin:0 auto;padding:38px 16px 70px}
.page-heading{padding:12px 0 28px;border-bottom:1px solid var(--line);margin-bottom:24px}
.eyebrow{font-size:11px;font-weight:800;letter-spacing:.2em;margin-bottom:12px;color:var(--muted)}
.page-heading h1{font-size:clamp(1.65rem,4vw,2.55rem);line-height:1.15;letter-spacing:-.03em;margin:0 0 10px}
.page-heading p{margin:0;color:var(--muted);font-size:.92rem}
.setting-box,.result-box{background:var(--paper);border:1px solid var(--line-strong)}
.setting-title{background:var(--note);border-bottom:1px solid var(--line-strong);color:var(--text);font-weight:800;padding:11px 16px;font-size:.95rem;letter-spacing:.06em}
.setting-section{padding:20px;border-bottom:1px solid var(--line)}.setting-section:last-of-type{border-bottom:0}
.setting-section h2{font-size:.95rem;margin:0 0 12px;display:flex;align-items:center;gap:8px}.setting-section h2::before{content:"";width:18px;height:1px;background:var(--text)}
.setting-section-head{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px}.setting-section-head h2{margin:0}
.small-actions{display:flex;gap:6px}.mini-btn{border:1px solid var(--line-strong);background:transparent;border-radius:0;padding:5px 9px;color:var(--text);font-size:.76rem;cursor:pointer}.mini-btn:hover{background:var(--note)}
.option-grid{display:grid;gap:8px}.year-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.subject-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
.select-card{position:relative;display:flex;align-items:center;min-height:50px;padding:10px 12px;border:1px solid var(--line-strong);background:var(--paper);cursor:pointer;gap:9px;transition:.12s}
.select-card:hover{background:var(--paper-soft)}.select-card:has(input:checked){background:var(--note);border-color:var(--text);box-shadow:inset 3px 0 0 var(--text)}
.select-card input,.toggle-line input{position:absolute;opacity:0;pointer-events:none}.fake-check{width:18px;height:18px;border:1px solid #777;background:#fff;display:inline-grid;place-items:center;flex:0 0 auto}
.select-card input:checked+.fake-check,.toggle-line input:checked+.fake-check{background:var(--text);border-color:var(--text)}.select-card input:checked+.fake-check::after,.toggle-line input:checked+.fake-check::after{content:"✓";color:#fff;font-size:13px;font-weight:900;line-height:1}
.select-card-main{font-weight:750}.select-card-sub{margin-left:auto;color:var(--muted);font-size:.77rem;white-space:nowrap}
.count-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:7px;max-width:520px}.count-grid label{cursor:pointer}.count-grid input{position:absolute;opacity:0}
.count-grid span{display:block;text-align:center;padding:9px 4px;border:1px solid var(--line-strong);background:#fff;font-weight:750;color:#555}.count-grid input:checked+span{background:var(--text);color:#fff;border-color:var(--text)}
.setting-note{margin:10px 0 0;color:var(--muted);font-size:.8rem}.compact-section{padding-top:15px;padding-bottom:15px}.toggle-line{position:relative;display:inline-flex;align-items:center;gap:9px;cursor:pointer;font-size:.9rem}
.selection-summary{padding:14px 20px;background:var(--paper-soft);border-top:1px solid var(--line);color:var(--muted);font-size:.88rem}.selection-summary strong{color:var(--text);font-size:1rem}
.start-area{padding:20px;text-align:center}.start-btn{min-width:220px;border:1px solid var(--text);border-radius:0;background:var(--text);color:#fff;padding:12px 26px;font-weight:800;letter-spacing:.04em;cursor:pointer}.start-btn:hover{background:#333}.start-btn:disabled{opacity:.4;cursor:not-allowed}
.caution-box{margin-top:16px;border-top:1px solid var(--line);padding:12px 0;font-size:.8rem;color:var(--muted)}.caution-box strong{color:var(--text);letter-spacing:.14em}.caution-box p{display:inline;margin:0 0 0 9px}
.quiz-heading-bar{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:10px}.back-link{border:0;background:none;color:var(--muted);text-decoration:underline;cursor:pointer;padding:5px 0;font-size:.84rem}.quiz-counter{font-size:.84rem;color:var(--muted);font-weight:700}
.question-panel{background:var(--paper);border:1px solid var(--line-strong)}.question-head{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:10px 13px;background:var(--note);border-bottom:1px solid var(--line-strong)}
.meta-pill{display:inline-block;background:transparent;border:1px solid var(--line-strong);color:#4d4d4d;padding:2px 7px;font-size:.74rem;margin-right:4px;font-weight:700}.question-no{font-size:.95rem}
.question-text{white-space:pre-wrap;padding:20px 18px 15px;font-size:1.04rem;font-weight:500;line-height:1.9;border-bottom:1px solid var(--line)}.choices{padding:13px 14px 5px;display:grid;gap:8px}
.choice-btn{display:grid;grid-template-columns:43px 1fr;align-items:stretch;text-align:left;padding:0;border:1px solid var(--line-strong);background:#fff;cursor:pointer;min-height:51px;overflow:hidden;color:var(--text)}
.choice-btn:hover:not(:disabled){background:var(--paper-soft);border-color:#777}.choice-btn.selected:not(:disabled){border:2px solid var(--text);background:var(--note)}
.choice-num{display:grid;place-items:center;background:#f0efeb;border-right:1px solid var(--line);font-weight:900;font-size:1.02rem}.choice-text{padding:10px 12px;white-space:pre-wrap;font-size:1rem;font-weight:500;line-height:1.75}
.choice-btn.correct{border-color:var(--green);background:var(--green-soft)}.choice-btn.correct .choice-num{background:#dcebdd;color:#29653a}.choice-btn.wrong{border-color:var(--red);background:var(--red-soft)}.choice-btn.wrong .choice-num{background:#f3d9d6;color:#983931}
.answer-btn{display:block;width:calc(100% - 28px);margin:13px 14px 18px;border:1px solid var(--text);background:var(--text);color:#fff;padding:11px 16px;font-weight:800;cursor:pointer}.answer-btn:disabled{opacity:.4;cursor:not-allowed}
.feedback{margin:18px 14px 20px;border:1px solid var(--line-strong);background:#fff}.feedback-result{padding:12px 14px;font-weight:900;font-size:1.15rem;border-bottom:1px solid var(--line)}.feedback.correct .feedback-result{color:var(--green);background:var(--green-soft)}.feedback.wrong .feedback-result{color:var(--red);background:var(--red-soft)}
.correct-answer{padding:11px 14px;background:#fff;border-bottom:1px solid var(--line);font-weight:500}.explain-title{padding:9px 14px;background:var(--note);border-bottom:1px solid var(--line-strong);font-weight:800;font-size:.9rem;letter-spacing:.05em}
.explanation-list{padding:6px 14px 10px}.explain-item{display:grid;grid-template-columns:34px 1fr;gap:7px;padding:9px 0;border-bottom:1px dotted var(--line-strong)}.explain-item:last-child{border-bottom:0}.explain-num{font-weight:900}.explain-choice{color:#444}.explain-choice strong{display:block;color:var(--text);margin-bottom:2px}
.note-block{padding:14px;border-top:1px solid var(--line)}.note-block p{margin:0;white-space:pre-wrap}.note-block-title{font-size:.78rem;font-weight:900;letter-spacing:.08em;color:var(--muted);margin-bottom:6px}.judgement-line{padding:11px 14px;border-top:1px solid var(--line);font-weight:750}.key-point{margin:0 14px 14px;padding:12px 13px;background:var(--note);border-left:3px solid var(--text)}.key-point strong{display:block;font-size:.76rem;letter-spacing:.08em;margin-bottom:3px}.related{padding:0 14px 14px;color:var(--muted);font-size:.78rem}
.quiz-nav{display:flex;justify-content:space-between;gap:9px;margin-top:12px}.nav-btn{border-radius:0;padding:10px 14px;font-weight:750;cursor:pointer}.nav-btn-sub{border:1px solid var(--line-strong);background:transparent;color:var(--text)}.nav-btn-main{border:1px solid var(--text);background:var(--text);color:#fff}.nav-btn:disabled{opacity:.35;cursor:not-allowed}
.result-body{text-align:center;padding:34px 18px}.score-main{font-size:clamp(1.5rem,6vw,2.3rem);font-weight:900}.score-detail{color:var(--muted);margin:8px 0 24px}.result-buttons{display:flex;justify-content:center;gap:10px;flex-wrap:wrap}
.site-footer{max-width:960px;margin:42px auto 0;border-top:1px solid var(--line);color:var(--muted);font-size:.7rem;padding:20px 16px;display:flex;justify-content:space-between;gap:20px;letter-spacing:.08em}
@media (max-width:640px){body{font-size:15px}.page-wrap{padding:25px 8px 50px}.top-header-inner{padding:14px 12px 10px}.brand-title{font-size:11px}.brand-sub{font-size:.69rem}.main-nav-inner{padding:7px 12px;font-size:.68rem}.page-heading{padding:8px 5px 20px;margin-bottom:14px}.page-heading h1{font-size:1.45rem}.page-heading p{font-size:.82rem}.setting-section{padding:15px 12px}.setting-title{padding:9px 12px}.year-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.subject-grid{grid-template-columns:1fr}.select-card{min-height:47px;padding:8px 9px}.select-card-sub{font-size:.71rem}.count-grid{grid-template-columns:repeat(4,1fr);gap:5px}.count-grid span{padding:8px 1px;font-size:.88rem}.small-actions{gap:4px}.mini-btn{font-size:.7rem;padding:4px 6px}.start-area{padding:15px 12px}.start-btn{width:100%;min-width:0}.question-head{padding:8px 9px}.question-text{padding:15px 12px 12px;font-size:1rem;font-weight:500;line-height:1.82}.choices{padding:10px 9px 3px}.choice-btn{grid-template-columns:38px 1fr}.choice-text{padding:9px}.answer-btn{width:calc(100% - 18px);margin:11px 9px 14px}.feedback{margin:13px 9px 15px}.feedback-result{font-size:1.05rem}.explanation-list{padding-left:10px;padding-right:10px}.explain-item{grid-template-columns:31px 1fr}.quiz-nav{position:sticky;bottom:0;background:rgba(243,241,236,.96);padding:7px 0 4px;z-index:5}.nav-btn{flex:1}.caution-box{font-size:.76rem}.site-footer{padding:18px 10px;flex-direction:column;gap:4px}}

/* v4: handwritten-note explanation display */
.point-explanation-only{padding:18px 14px 20px;border-top:0;}
.point-explanation-only .note-block-title{margin-bottom:12px;}
.point-explanation-text{line-height:1.9;color:var(--text);font-size:1rem;font-weight:500;}
.point-section-label{margin:22px 0 7px;font-weight:900;font-size:1rem;letter-spacing:.02em;color:var(--text);}
.point-section-label:first-child{margin-top:0;}
.point-line{white-space:pre-wrap;}
.point-spacer{height:8px;}
@media (max-width:640px){.point-explanation-only{padding:15px 12px 18px}.point-explanation-text{font-size:.98rem;font-weight:500;line-height:1.85}.point-section-label{margin-top:19px;font-size:.98rem}.point-spacer{height:6px}}

/* v6: approved handwritten explanations are shown directly to prevent any summarization or wording drift. */
.point-explanation-image{margin-top:12px;background:#fff;}
.point-explanation-image img{display:block;width:100%;height:auto;border:1px solid var(--line-strong);background:#fff;}
@media (max-width:640px){.point-explanation-image{margin-top:10px}.point-explanation-image img{width:100%;}}

/* v7: question text readability — remove PDF wrap breaks and show statements as separate blocks */
.question-text{
  white-space:normal;
  padding:0;
  font-size:1.04rem;
  font-weight:500;
  line-height:1.9;
  border-bottom:1px solid var(--line);
}
.question-content{padding:18px 18px 16px;}
.question-paragraph{
  margin:0 0 16px;
  line-height:1.95;
  letter-spacing:.025em;
  overflow-wrap:anywhere;
}
.question-paragraph:last-child{margin-bottom:0;}
.question-lead{
  padding:2px 0 17px;
  margin-bottom:17px;
  border-bottom:1px solid var(--line);
  font-weight:500;
}
.statement-block{
  display:grid;
  grid-template-columns:38px minmax(0,1fr);
  gap:10px;
  align-items:start;
  margin:0 0 12px;
  padding:14px 14px 14px 10px;
  background:#fff;
  border:1px solid var(--line);
}
.statement-block:last-child{margin-bottom:0;}
.statement-label{
  width:30px;
  height:30px;
  display:grid;
  place-items:center;
  border-radius:5px;
  background:#5a5753;
  color:#fff;
  font-weight:900;
  line-height:1;
  margin-top:1px;
}
.statement-text{
  line-height:1.95;
  letter-spacing:.025em;
  overflow-wrap:anywhere;
}

/* Navigation must not cover the end of the question on mobile. */
@media (max-width:640px){
  .question-content{padding:15px 11px 13px;}
  .question-text{font-size:1.02rem;font-weight:500;line-height:1.9;}
  .question-paragraph{margin-bottom:14px;line-height:1.9;}
  .question-lead{padding-bottom:14px;margin-bottom:14px;}
  .statement-block{grid-template-columns:34px minmax(0,1fr);gap:8px;padding:12px 10px 12px 8px;margin-bottom:10px;}
  .statement-label{width:28px;height:28px;font-size:.95rem;border-radius:5px;}
  .statement-text{line-height:1.9;}
  .quiz-nav{position:static;background:transparent;padding:0;margin-top:12px;}
}

/* v8: temporary memory mark — click/tap the question text to toggle a green circle */
.memory-mark-target{
  position:relative;
  cursor:pointer;
  -webkit-tap-highlight-color:transparent;
  user-select:text;
}
.memory-mark-target::after{
  content:"";
  position:absolute;
  right:12px;
  top:50%;
  width:28px;
  height:28px;
  border:3px solid var(--green);
  border-radius:50%;
  transform:translateY(-50%) scale(.75);
  opacity:0;
  pointer-events:none;
  transition:opacity .12s ease,transform .12s ease;
}
.memory-mark-target.memory-marked::after{
  opacity:1;
  transform:translateY(-50%) scale(1);
}
.statement-block.memory-mark-target{
  padding-right:52px;
}.memory-mark-target:focus-visible{
  outline:2px solid var(--green);
  outline-offset:2px;
}

@media (max-width:640px){
  .memory-mark-target::after{
    right:9px;
    width:26px;
    height:26px;
    border-width:3px;
  }
  .statement-block.memory-mark-target{
    padding-right:44px;
  }}

/* v9: structured calculation questions and official problem figures */
.structured-question .question-lead{margin-bottom:0;}
.design-conditions{padding:17px 0 0;}
.design-conditions-title{font-weight:800;margin:0 0 10px;letter-spacing:.03em;}
.design-condition-row{
  display:grid;
  grid-template-columns:34px minmax(0,1fr);
  gap:8px;
  align-items:start;
  padding:7px 0;
  border-bottom:1px dotted var(--line);
}
.design-condition-row:last-child{border-bottom:0;}
.design-condition-label{font-weight:900;line-height:1.8;text-align:center;}
.design-condition-text{line-height:1.85;letter-spacing:.02em;overflow-wrap:anywhere;}
.question-visuals{padding:0 18px 18px;display:grid;gap:16px;}
.question-visual{margin:0;border-top:1px solid var(--line);padding-top:14px;}
.question-visual figcaption{font-size:.78rem;font-weight:800;color:var(--muted);letter-spacing:.05em;margin-bottom:8px;}
.question-visual-scroll{
  overflow:hidden;
  background:#fff;
  border:1px solid var(--line);
  padding:6px;
}
.question-visual a{
  display:block;
  width:100%;
  line-height:0;
  cursor:zoom-in;
}
.question-visual img{
  display:block;
  width:100%;
  max-width:100%;
  height:auto;
  object-fit:contain;
  margin:0 auto;
  background:#fff;
}
.question-visual.is-table .question-visual-scroll{
  padding:6px;
}
.question-visual.is-table img{
  width:100%;
  max-width:100%;
  min-width:0;
  height:auto;
}
@media (max-width:640px){
  .design-conditions{padding-top:14px;}
  .design-condition-row{grid-template-columns:30px minmax(0,1fr);gap:7px;padding:7px 0;}
  .design-condition-text{line-height:1.8;}
  .question-visuals{padding:0 11px 13px;gap:13px;}
  .question-visual{padding-top:11px;}
  .question-visual figcaption{font-size:.74rem;}
  .question-visual-scroll{padding:4px;}
  .question-visual.is-table .question-visual-scroll{padding:4px;}
  .question-visual.is-table img{
    width:100%;
    max-width:100%;
    min-width:0;
  }
}