.chemistry-tools-spdf{
  --card:#ffffff;
  --ink:#172033;
  --muted:#657086;
  --line:#dbe3ef;
  --accent:#2857c5;
  --accent-soft:#eef3ff;
  --success:#16794b;
  --error:#9b2525;

  font-family:Arial,Helvetica,sans-serif;
  color:var(--ink);
  line-height:1.5;
}

.chemistry-tools-spdf,
.chemistry-tools-spdf *{
  box-sizing:border-box;
}

.chemistry-tools-spdf .page{
  max-width:980px;
  margin:0 auto;
  padding:28px 18px 50px;
}

.chemistry-tools-spdf h1{
  margin:0 0 6px;
  font-size:clamp(28px,4vw,40px);
}

.chemistry-tools-spdf .subtitle{
  color:var(--muted);
  margin:0 0 22px;
}

.chemistry-tools-spdf .card{
  background:var(--card);
  border:1px solid var(--line);
  border-radius:14px;
  padding:20px;
  box-shadow:0 4px 18px rgba(30,55,90,.05);
  margin-bottom:18px;
}

.chemistry-tools-spdf .toolbar{
  display:flex;
  gap:16px;
  flex-wrap:wrap;
  align-items:flex-end;
  justify-content:space-between;
}

.chemistry-tools-spdf .field{
  flex:1;
  min-width:220px;
}

.chemistry-tools-spdf .question-field{
  max-width:310px;
}

.chemistry-tools-spdf label{
  display:block;
  font-weight:700;
  margin-bottom:6px;
}

.chemistry-tools-spdf input,
.chemistry-tools-spdf select,
.chemistry-tools-spdf textarea{
  width:100%;
  padding:11px 12px;
  border:1px solid #bcc8da;
  border-radius:9px;
  font-size:16px;
  background:#fff;
  color:var(--ink);
}

.chemistry-tools-spdf textarea{
  resize:vertical;
  min-height:84px;
  font-family:"Cambria Math","Times New Roman",serif;
  font-size:18px;
}

.chemistry-tools-spdf input:focus,
.chemistry-tools-spdf select:focus,
.chemistry-tools-spdf textarea:focus{
  outline:3px solid rgba(40,87,197,.15);
  border-color:var(--accent);
}

.chemistry-tools-spdf button{
  padding:12px 18px;
  border:0;
  border-radius:9px;
  background:var(--accent);
  color:#fff;
  font-size:16px;
  font-weight:700;
  cursor:pointer;
}

.chemistry-tools-spdf button.secondary{
  background:#fff;
  color:var(--accent);
  border:1px solid var(--accent);
}

.chemistry-tools-spdf button:hover{
  filter:brightness(.96);
}

.chemistry-tools-spdf .button-row,
.chemistry-tools-spdf .answer-buttons{
  display:flex;
  gap:8px;
  flex-wrap:wrap;
}

.chemistry-tools-spdf .answer-buttons{
  margin-top:14px;
}

.chemistry-tools-spdf .hint{
  color:var(--muted);
  font-size:13px;
  margin-top:6px;
}

.chemistry-tools-spdf .question-label{
  color:var(--muted);
  font-size:14px;
  font-weight:700;
  margin-bottom:8px;
  text-transform:uppercase;
  letter-spacing:.04em;
}

.chemistry-tools-spdf .question-text{
  font-size:21px;
  line-height:1.6;
  margin-bottom:20px;
}

.chemistry-tools-spdf .species{
  display:inline-block;
  font-family:"Cambria Math","Times New Roman",serif;
  font-size:30px;
  font-weight:700;
  padding:4px 10px;
  background:#f8faff;
  border:1px solid var(--line);
  border-radius:9px;
  margin:4px 0;
}

.chemistry-tools-spdf .answer-area{
  margin-top:18px;
  padding-top:18px;
  border-top:1px solid var(--line);
}

.chemistry-tools-spdf .feedback{
  display:none;
  margin-top:14px;
  padding:13px;
  border-radius:9px;
}

.chemistry-tools-spdf .feedback.good{
  display:block;
  background:#eefaf4;
  border:1px solid #ccebdc;
  color:var(--success);
}

.chemistry-tools-spdf .feedback.bad{
  display:block;
  background:#fff2f2;
  border:1px solid #efc7c7;
  color:var(--error);
}

.chemistry-tools-spdf .solution{
  margin-top:18px;
  padding:16px;
  border:1px solid var(--line);
  border-radius:10px;
  background:#fbfcff;
}

.chemistry-tools-spdf .solution-title{
  font-weight:700;
  margin-bottom:8px;
}

.chemistry-tools-spdf .configuration{
  font-family:"Cambria Math","Times New Roman",serif;
  font-size:21px;
  line-height:1.8;
  overflow-wrap:anywhere;
}

.chemistry-tools-spdf .note{
  color:var(--muted);
  font-size:14px;
  margin-top:10px;
}

@media(max-width:720px){

  .chemistry-tools-spdf .button-row{
    width:100%;
  }

  .chemistry-tools-spdf .button-row button,
  .chemistry-tools-spdf .answer-buttons button{
    flex:1 1 140px;
  }
}