*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: Georgia, 'Times New Roman', serif;
  background: #f5f0eb;
  color: #3b2f2f;
  line-height: 1.6;
  min-height: 100vh;
}

header {
  background: #5c3d2e;
  color: #f5f0eb;
  padding: 1rem 1.5rem;
}
header h1 { font-size: 1.5rem; }
header a {
  color: #d4c4b0;
  text-decoration: none;
  font-size: 0.9rem;
}
header a:hover { color: #fff; }

.layout {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  padding: 1.5rem;
  max-width: 1400px;
  margin: 0 auto;
}

/* --- Form panel --- */
.form-panel {
  flex: 0 0 320px;
  background: #fff;
  border: 1px solid #d4c4b0;
  border-radius: 8px;
  padding: 1.25rem;
  align-self: flex-start;
  position: sticky;
  top: 1rem;
}
.form-panel h2 {
  font-size: 1.1rem;
  color: #5c3d2e;
  margin-bottom: 1rem;
  border-bottom: 1px solid #e8ddd2;
  padding-bottom: 0.5rem;
}
.form-group {
  margin-bottom: 0.75rem;
}
.form-group label {
  display: block;
  font-size: 0.85rem;
  color: #7a5c4f;
  margin-bottom: 0.2rem;
}
.input-row {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
.input-row input {
  flex: 1;
  min-width: 0;
}
.stepper {
  flex-shrink: 0;
  width: 1.6rem;
  height: 1.6rem;
  border: 1px solid #d4c4b0;
  border-radius: 4px;
  background: #faf8f5;
  color: #7a5c4f;
  font-size: 1rem;
  line-height: 1;
  cursor: pointer;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  touch-action: manipulation;
  -webkit-user-select: none;
  user-select: none;
}
.stepper:active {
  background: #e8ddd2;
}
.imperial {
  flex-shrink: 0;
  font-size: 0.85rem;
  font-weight: bold;
  color: #5c3d2e;
  white-space: nowrap;
  min-width: 4.5em;
}
.form-group input {
  width: 100%;
  padding: 0.4rem 0.5rem;
  border: 1px solid #d4c4b0;
  border-radius: 4px;
  font-size: 0.95rem;
  font-family: inherit;
  color: #3b2f2f;
  background: #faf8f5;
}
.form-group input:focus {
  outline: none;
  border-color: #a0845e;
  box-shadow: 0 0 0 2px rgba(160, 132, 94, 0.2);
}
.form-group.has-error label {
  color: #c00;
}
.validation-error {
  font-size: 0.75rem;
  color: #c00;
  font-style: italic;
  margin-left: 0.5rem;
}

/* --- Cut list --- */
.cut-list {
  background: #fff;
  border: 1px solid #d4c4b0;
  border-radius: 8px;
  padding: 1.25rem;
  flex: 0 0 320px;
  align-self: flex-start;
}
.cut-list h2 {
  font-size: 1.1rem;
  color: #5c3d2e;
  margin-bottom: 1rem;
  border-bottom: 1px solid #e8ddd2;
  padding-bottom: 0.5rem;
}
.cut-list table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
.cut-list th, .cut-list td {
  text-align: left;
  padding: 0.35rem 0.5rem;
  border-bottom: 1px solid #e8ddd2;
}
.cut-list th {
  color: #7a5c4f;
  font-weight: normal;
  font-size: 0.8rem;
}
.cut-list .section-heading {
  font-size: 0.95rem;
  color: #5c3d2e;
  margin: 1rem 0 0.5rem;
}
.cut-list .section-heading:first-child {
  margin-top: 0;
}
.derived-values dt {
  font-size: 0.8rem;
  color: #7a5c4f;
  margin-top: 0.5rem;
}
.derived-values dd {
  font-size: 0.95rem;
  font-weight: bold;
  color: #5c3d2e;
}

/* --- Diagram area --- */
.diagrams {
  flex: 1 1 600px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: 1.5rem;
}
.diagram-card {
  background: #fff;
  border: 1px solid #d4c4b0;
  border-radius: 8px;
  padding: 1rem;
}
.diagram-card h3 {
  font-size: 0.95rem;
  color: #5c3d2e;
  margin-bottom: 0.75rem;
  border-bottom: 1px solid #e8ddd2;
  padding-bottom: 0.4rem;
}
.diagram-card svg {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 6px;
  background: linear-gradient(180deg, #fffdfb 0%, #f7f2ec 100%);
  box-shadow: inset 0 0 0 1px rgba(92, 61, 46, 0.08);
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .layout {
    flex-direction: column;
  }
  .form-panel, .cut-list {
    flex: 1 1 auto;
    position: static;
  }
  .diagrams {
    grid-template-columns: 1fr;
  }
  .stepper {
    width: 2.75rem;
    height: 2.75rem;
    font-size: 1.25rem;
    border-radius: 6px;
  }
}