:root {
  --bg-color: #f4f4f4;
  --card-color: #ffffff;
  --text-color: #1f2937;
  --muted-text: #5b6472;
  --border-color: #d9e0ea;
  --accent-color: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-soft: #e8f0ff;
  --success-bg: #e9f8ef;
  --success-text: #156f3d;
  --error-bg: #fdecec;
  --error-text: #b42318;
  --shadow: 0 14px 32px rgba(31, 41, 55, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 32px 16px;
  font-family: Arial, sans-serif;
  background: #f9fbff;
  color: var(--text-color);
}

.page {
  max-width: 920px;
  margin: 0 auto;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  margin-bottom: 24px;
}

.nav-link {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 999px;
  background: var(--card-color);
  color: var(--text-color);
  text-decoration: none;
  font-weight: bold;
  border: 1px solid var(--border-color);
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.nav-link:hover,
.nav-link:focus-visible {
  background: var(--accent-soft);
  border-color: #bcd0ff;
  outline: none;
}

.nav-link.active {
  background: var(--accent-color);
  color: #ffffff;
  border-color: var(--accent-color);
}

.card {
  background: var(--card-color);
  border-radius: 18px;
  padding: 24px;
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}

.intro-card {
  text-align: left;
}

h1,
h2,
h3 {
  margin-top: 0;
}

h1 {
  margin-bottom: 12px;
  text-align: left;
}

h2 {
  margin-bottom: 10px;
}

.section-intro {
  margin-top: 0;
  margin-bottom: 18px;
  color: var(--muted-text);
  line-height: 1.6;
}

.field-group {
  margin-bottom: 16px;
}

label {
  display: block;
  margin-bottom: 6px;
  font-weight: bold;
}

input,
select,
button {
  font: inherit;
}

input,
select {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: #ffffff;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus,
select:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
  outline: none;
}

button {
  border: none;
  border-radius: 12px;
  padding: 12px 18px;
  background: var(--accent-color);
  color: #ffffff;
  font-weight: bold;
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.2s ease;
}

button:hover,
button:focus-visible {
  background: var(--accent-hover);
  transform: translateY(-1px);
  outline: none;
}

button:disabled {
  background: #a6b4d5;
  cursor: not-allowed;
  transform: none;
}

.button-secondary {
  background: #eef2f8;
  color: var(--text-color);
  border: 1px solid var(--border-color);
}

.button-secondary:hover,
.button-secondary:focus-visible {
  background: #e4ebf6;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 8px;
}

.rows-stack {
  display: grid;
  gap: 16px;
}

.dynamic-row {
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 18px;
  background: #fbfcff;
}

.row-grid {
  display: grid;
  gap: 14px;
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr) minmax(0, 1fr) auto;
  align-items: end;
}

.course-row .row-grid {
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.9fr) minmax(0, 1fr) minmax(0, 0.9fr) auto;
}

.remove-row-btn {
  min-width: 108px;
}

.helper-text,
.form-note {
  margin-top: 0;
  color: var(--muted-text);
  line-height: 1.5;
}

.message {
  margin-top: 18px;
  padding: 12px 14px;
  border-radius: 12px;
  font-weight: bold;
}

.message.success {
  background: var(--success-bg);
  color: var(--success-text);
}

.message.error {
  background: var(--error-bg);
  color: var(--error-text);
}

.hidden {
  display: none;
}

.results-panel {
  margin-top: 20px;
  padding: 18px;
  border-radius: 16px;
  background: #f8fbff;
  border: 1px solid #dbe7ff;
}

.table-wrapper {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 620px;
}

th,
td {
  padding: 12px;
  border-bottom: 1px solid var(--border-color);
  text-align: left;
}

thead th {
  background: #edf4ff;
  color: #20304d;
}

tfoot th,
tfoot td {
  font-weight: bold;
  background: #f5f9ff;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin-bottom: 18px;
}

.summary-box {
  padding: 16px;
  border-radius: 14px;
  background: #ffffff;
  border: 1px solid var(--border-color);
}

.summary-label {
  display: block;
  margin-bottom: 6px;
  color: var(--muted-text);
  font-size: 14px;
}

.summary-value {
  font-size: 24px;
  font-weight: bold;
}

.scale-card {
  margin-top: 18px;
  padding: 16px;
  border-radius: 14px;
  background: #f8fbff;
  border: 1px solid #dbe7ff;
}

@media (max-width: 760px) {
  body {
    padding: 20px 12px;
  }

  .card {
    padding: 20px;
  }

  .row-grid,
  .course-row .row-grid {
    grid-template-columns: 1fr;
  }

  .remove-row-btn,
  .button-row button {
    width: 100%;
  }

  table {
    min-width: 100%;
  }
}