#formulaInputArea {
  margin-bottom: 2rem;
}

#formulaForm {
  display: flex;
  gap: 0;
  flex-direction: column;
}

#formulaForm label {
  display: block;
  margin-top: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.95rem;
}

#formulaGradeLevel,
#formulaQuery {
  width: 100%;
  padding: 0.875rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  margin-top: 0.5rem;
  font-family: inherit;
  transition: all 0.3s;
  background: var(--bg-secondary);
  color: var(--text-primary);
}

#formulaGradeLevel {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 3rem;
}

#formulaGradeLevel:hover {
  border-color: var(--accent-color);
}

#formulaGradeLevel option {
  padding: 0.75rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
}

#formulaGradeLevel:focus,
#formulaQuery:focus {
  outline: none;
  border-color: var(--accent-color);
  background: var(--bg-primary);
  box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.1);
}

#formulaQuery::placeholder {
  color: var(--text-secondary);
  opacity: 0.7;
}

#formulaSubmitBtn {
  width: 100%;
  padding: 1rem;
  background: var(--accent-color);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  margin-top: 1.75rem;
  transition: background 0.2s ease;
}

#formulaSubmitBtn:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
}

#formulaSubmitBtn:active {
  transform: translateY(0);
}

#formulaSubmitBtn:disabled {
  background: var(--text-tertiary);
  cursor: not-allowed;
  transform: none;
}

#formulaResultArea {
  animation: fadeIn 0.4s ease-in;
}

.formula-result {
  background: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: 10px;
  padding: 2rem;
  margin-bottom: 1.5rem;
  overflow-x: auto;
  transition: all 0.3s ease;
}

.formula-result:hover {
  border-color: var(--accent-color);
}

.search-another-btn {
  width: 100%;
  padding: 0.875rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 2px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
}

.search-another-btn:hover {
  background: var(--accent-color);
  color: #fff;
  border-color: var(--accent-color);
  transform: translateY(-2px);
}

.search-another-btn:active {
  transform: translateY(0);
}

.loading {
  text-align: center;
  padding: 2rem;
  color: var(--text-secondary);
  font-size: 1.1rem;
}

.loading::after {
  content: "...";
  animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
  0%,
  20% {
    content: ".";
  }
  40% {
    content: "..";
  }
  60%,
  100% {
    content: "...";
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 640px) {
  .formula-result {
    padding: 1.5rem;
  }

  #formulaQuery {
    font-size: 0.95rem;
    padding: 0.875rem 1rem;
  }

  #formulaSubmitBtn {
    font-size: 0.95rem;
    padding: 0.875rem;
  }
}