:root {
  --bg: #f5f7fb;
  --panel: #ffffff;
  --ink: #18202f;
  --muted: #667085;
  --line: #dde3ee;
  --primary: #1f6feb;
  --primary-strong: #174ea6;
  --accent: #0f9f7a;
  --warning: #be6b00;
  --shadow: 0 18px 45px rgba(28, 39, 64, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  font-family: Arial, "Noto Sans KR", sans-serif;
  color: var(--ink);
  background:
    linear-gradient(135deg, rgba(31, 111, 235, 0.12), transparent 36%),
    linear-gradient(315deg, rgba(15, 159, 122, 0.12), transparent 38%),
    var(--bg);
}

button,
input,
select {
  font: inherit;
}

.site-header {
  max-width: 1120px;
  margin: 0 auto;
  padding: 48px 24px 22px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--primary);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2 {
  margin: 0;
  letter-spacing: 0;
}

h1 {
  font-size: clamp(34px, 6vw, 58px);
  line-height: 1.05;
}

h2 {
  font-size: 28px;
}

.subtitle {
  max-width: 690px;
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.65;
  overflow-wrap: anywhere;
}

.app-shell {
  display: grid;
  grid-template-columns: minmax(220px, 290px) minmax(0, 1fr);
  gap: 22px;
  width: calc(100% - 48px);
  max-width: 1120px;
  margin: 0 auto 54px;
}

.calculator-nav,
.calculator-panel {
  max-width: 100%;
  background: rgba(255, 255, 255, 0.88);
  border: 1px solid rgba(221, 227, 238, 0.9);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
}

.calculator-nav {
  display: grid;
  align-content: start;
  gap: 8px;
  padding: 12px;
  border-radius: 18px;
}

.nav-button {
  display: grid;
  grid-template-columns: 40px 1fr;
  align-items: center;
  gap: 10px;
  min-height: 58px;
  padding: 10px 12px;
  border: 1px solid transparent;
  border-radius: 12px;
  color: var(--ink);
  background: transparent;
  cursor: pointer;
  text-align: left;
  font-weight: 700;
}

.nav-button:hover,
.nav-button:focus-visible {
  border-color: var(--line);
  background: #f7faff;
  outline: none;
}

.nav-button.active {
  border-color: rgba(31, 111, 235, 0.28);
  background: #eaf2ff;
  color: var(--primary-strong);
}

.nav-icon {
  display: inline-grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: #edf3fb;
  color: var(--primary-strong);
  font-size: 14px;
  font-weight: 800;
}

.calculator-panel {
  min-height: 560px;
  padding: 28px;
  border-radius: 20px;
}

.panel-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.status-badge {
  flex: 0 0 auto;
  padding: 9px 12px;
  border-radius: 999px;
  color: #0b604c;
  background: #dbf7ef;
  font-size: 13px;
  font-weight: 800;
}

.calculator-form {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.field,
.full-row {
  display: grid;
  gap: 8px;
}

.full-row {
  grid-column: 1 / -1;
}

label {
  color: #344054;
  font-size: 14px;
  font-weight: 800;
}

input,
select {
  width: 100%;
  min-height: 48px;
  padding: 11px 13px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink);
  background: #ffffff;
}

input[type="checkbox"] {
  width: 18px;
  min-height: 18px;
  accent-color: var(--primary);
}

input:focus,
select:focus {
  border-color: var(--primary);
  outline: 3px solid rgba(31, 111, 235, 0.16);
}

.subject-list {
  display: grid;
  gap: 12px;
}

.subject-row {
  display: grid;
  grid-template-columns: minmax(160px, 1.4fr) minmax(96px, 0.8fr) minmax(96px, 0.8fr) 86px 72px;
  align-items: end;
  gap: 10px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fbfdff;
}

.major-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 48px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #ffffff;
  color: var(--ink);
  cursor: pointer;
}

.major-toggle span {
  font-size: 14px;
  font-weight: 800;
}

.icon-button {
  min-height: 48px;
  padding: 0 12px;
  border: 1px solid #f0c8c8;
  border-radius: 10px;
  color: #a13b3b;
  background: #fff7f7;
  cursor: pointer;
  font-weight: 800;
}

.icon-button:hover {
  background: #ffecec;
}

.hint {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  grid-column: 1 / -1;
  margin-top: 4px;
}

.primary-button,
.secondary-button {
  min-height: 46px;
  padding: 0 18px;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  font-weight: 800;
}

.primary-button {
  color: #ffffff;
  background: var(--primary);
}

.primary-button:hover {
  background: var(--primary-strong);
}

.secondary-button {
  color: var(--ink);
  border-color: var(--line);
  background: #ffffff;
}

.secondary-button:hover {
  background: #f7f9fc;
}

.result-area {
  margin-top: 26px;
  padding: 22px;
  border: 1px solid #caeadf;
  border-radius: 16px;
  background: linear-gradient(135deg, #f0fcf8, #f7fbff);
}

.result-label {
  margin: 0 0 8px;
  color: #0b604c;
  font-size: 13px;
  font-weight: 800;
}

#result-main {
  display: block;
  color: #0c3d33;
  font-size: 30px;
  line-height: 1.25;
}

#result-sub {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.55;
}

@media (max-width: 800px) {
  .site-header {
    padding-top: 34px;
  }

  .app-shell {
    grid-template-columns: 1fr;
    width: calc(100% - 28px);
    max-width: 620px;
  }

  .calculator-nav {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .calculator-panel {
    min-height: auto;
    padding: 22px;
  }

  .subject-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .subject-name-field {
    grid-column: 1 / -1;
  }
}

@media (max-width: 560px) {
  .calculator-nav,
  .calculator-form {
    grid-template-columns: 1fr;
  }

  .panel-header {
    display: grid;
  }

  h2 {
    font-size: 24px;
  }

  #result-main {
    font-size: 24px;
  }

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

  .major-toggle {
    justify-content: flex-start;
  }
}