* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #f3f0ea;
  color: #1f2428;
  line-height: 1.55;
}

.page {
  max-width: 1120px;
  margin: 0 auto;
  padding: 42px 20px 70px;
}

.hero {
  text-align: center;
  padding: 36px 0 24px;
}

.tag {
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.8rem;
  color: #666;
  font-weight: bold;
}

h1 {
  font-size: clamp(2.2rem, 7vw, 5rem);
  line-height: 1.05;
  margin: 10px 0 14px;
}

h1 span {
  color: #4f565c;
}

.hero p {
  max-width: 820px;
  margin: 0 auto;
  color: #4f565c;
  font-size: 1.08rem;
}

.card {
  background: white;
  border: 1px solid #ded8cf;
  border-radius: 22px;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.07);
  padding: 26px;
  margin-top: 24px;
}

h2 {
  margin-top: 0;
}

.hint {
  color: #586069;
}

textarea {
  width: 100%;
  min-height: 110px;
  border: 1px solid #bbb;
  border-radius: 14px;
  padding: 14px;
  font-size: 1rem;
  resize: vertical;
  outline: none;
}

textarea:focus,
input:focus,
select:focus {
  border-color: #1f2428;
  outline: none;
}

.button-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin: 16px 0;
}

button {
  border: none;
  background: #1f2428;
  color: white;
  padding: 12px 18px;
  border-radius: 999px;
  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background: #3a4148;
}

button.secondary {
  background: #e8e3d9;
  color: #1f2428;
}

.answer-box,
.guide-panel {
  background: #f8f6f1;
  border-left: 5px solid #1f2428;
  border-radius: 12px;
  padding: 18px;
  min-height: 90px;
  white-space: pre-line;
  color: #1f2428;
  overflow-wrap: break-word;
}

.formula-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(245px, 1fr));
  gap: 12px;
  margin: 18px 0 22px;
}

.formula-list button {
  border-radius: 14px;
  text-align: left;
  background: #f0ece4;
  color: #1f2428;
  line-height: 1.25;
}

.formula-list button:hover {
  background: #ded8cf;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 12px;
  margin: 14px 0;
}

label {
  display: flex;
  flex-direction: column;
  font-weight: bold;
  gap: 6px;
  color: #30363d;
}

input,
select {
  width: 100%;
  border: 1px solid #bbb;
  border-radius: 10px;
  padding: 10px;
  font-size: 1rem;
  background: white;
}

.small {
  font-size: 0.92rem;
  color: #586069;
}

.output {
  margin-top: 14px;
  padding: 14px;
  background: white;
  border: 1px solid #ded8cf;
  border-radius: 12px;
  white-space: pre-line;
}

@media (max-width: 650px) {
  .card {
    padding: 20px;
  }
}