.gcd-tool {
  background: #ffffff;
  border: 1px solid var(--math-line);
  border-radius: 18px;
  box-shadow: var(--math-shadow);
  overflow: hidden;
}


.gcd-tool-head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 20px;
  padding: 25px 28px 20px;
  border-bottom: 1px solid var(--math-line);
}


.gcd-tool-head h1 {
  margin: 0 0 7px;
  font-size: 30px;
}


.gcd-tool-head p {
  margin: 0;
  color: var(--math-text-soft);
  font-size: 13px;
  line-height: 1.7;
}


.gcd-grade {
  flex: 0 0 auto;
  padding: 6px 9px;
  background: var(--math-elementary-soft);
  border-radius: 8px;
  color: #287a51;
  font-size: 11px;
  font-weight: 800;
}


.gcd-workspace {
  display: grid;
  grid-template-columns:
    minmax(0, 1.35fr)
    minmax(300px, 0.8fr);
}


.gcd-input-panel {
  min-width: 0;
  padding: 25px 28px;
  border-right: 1px solid var(--math-line);
}


.gcd-input-panel h2 {
  margin: 0 0 14px;
  font-size: 16px;
}


.gcd-input-label {
  display: block;
  margin-bottom: 7px;
  color: var(--math-text-soft);
  font-size: 12px;
  font-weight: 700;
}


.gcd-input {
  width: 100%;
  height: 52px;
  padding: 0 14px;
  border: 1px solid var(--math-line);
  border-radius: 9px;
  font-size: 18px;
  font-weight: 700;
  outline: none;
}


.gcd-input:focus {
  border-color: var(--math-primary);
  box-shadow:
    0 0 0 3px
    rgba(47, 111, 237, 0.1);
}


.gcd-actions {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 20px;
}


.gcd-actions button {
  min-height: 44px;
  border: 0;
  border-radius: 9px;
  font-weight: 800;
  cursor: pointer;
}


.gcd-calculate {
  min-width: 180px;
  background: var(--math-primary);
  color: #ffffff;
}


.gcd-clear {
  min-width: 76px;
  background: #eef1f6;
  color: #566176;
}


.gcd-error {
  margin: 14px 0 0;
  color: #c0392b;
  text-align: center;
  font-size: 12px;
  font-weight: 700;
}


.gcd-result-panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 220px;
  padding: 24px;
  background: #f8faff;
}


.gcd-result-label {
  margin-bottom: 8px;
  color: var(--math-text-soft);
  font-size: 12px;
  font-weight: 800;
}


.gcd-result {
  color: var(--math-primary);
  font-size: 46px;
  font-weight: 900;
}


.gcd-numbers {
  margin-top: 8px;
  color: var(--math-text-soft);
  font-size: 13px;
}


.gcd-steps {
  padding: 22px 28px 27px;
  border-top: 1px solid var(--math-line);
}


.gcd-steps-head h2 {
  margin: 0 0 12px;
  font-size: 16px;
}


.gcd-steps-list {
  display: grid;
  gap: 7px;
}


.gcd-step {
  display: flex;
  gap: 12px;
  padding: 10px 12px;
  background: #f7f9fc;
  border-radius: 9px;
}


.gcd-step-number {
  flex: 0 0 auto;
  width: 24px;
  height: 24px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--math-primary-soft);
  border-radius: 50%;
  color: var(--math-primary);
  font-size: 11px;
  font-weight: 900;
}


.gcd-step-text {
  color: #43506a;
  font-size: 13px;
  line-height: 1.7;
}


.gcd-info-grid {
  display: grid;
  grid-template-columns:
    repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 20px;
}


.gcd-info-card {
  padding: 18px;
  background: #ffffff;
  border: 1px solid var(--math-line);
  border-radius: 13px;
}


.gcd-info-card h2 {
  margin: 0 0 8px;
  font-size: 15px;
}


.gcd-info-card p {
  margin: 0;
  color: var(--math-text-soft);
  font-size: 12px;
  line-height: 1.7;
}


@media (max-width: 760px) {

  .gcd-workspace {
    grid-template-columns: 1fr;
  }


  .gcd-input-panel {
    border-right: 0;
    border-bottom: 1px solid var(--math-line);
  }


  .gcd-result-panel {
    min-height: 160px;
  }

}


@media (max-width: 520px) {

  .gcd-tool-head {
    padding: 20px 18px;
  }


  .gcd-tool-head h1 {
    font-size: 26px;
  }


  .gcd-grade {
    display: none;
  }


  .gcd-input-panel {
    padding: 20px 14px;
  }


  .gcd-input {
    font-size: 16px;
  }


  .gcd-result {
    font-size: 38px;
  }


  .gcd-info-grid {
    grid-template-columns: 1fr;
  }

}