@import url('https://fonts.googleapis.com/css2?family=Merriweather:wght@400;700&family=Roboto:wght@400;500;700&family=Source+Sans+3:wght@400;600;700&display=swap');

:root {
  --bg: #f5f6f7;
  --panel: #ffffff;
  --text: #1c1f23;
  --muted: #5c6670;
  --accent: #1f4e79;
  --accent-soft: #d9e4ef;
  --button: #eef1f4;
  --button-hover: #dfe6ee;
  --border: #cfd6dd;
  --shadow: 0 12px 24px rgba(16, 24, 40, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Source Sans 3', sans-serif;
  background: linear-gradient(180deg, #f8f9fb 0%, #eef2f6 100%);
  color: var(--text);
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover {
  color: var(--accent);
}

.site-header {
  display: grid;
  grid-template-columns: 1fr auto 220px 220px;
  align-items: center;
  gap: 24px;
  padding: 20px 6vw;
  background: #eef5ff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand .logo {
  font-family: 'Merriweather', serif;
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent);
}

.brand .logo span {
  color: var(--text);
}

.tagline {
  color: var(--muted);
  font-size: 0.95rem;
}

.main-nav {
  display: flex;
  gap: 18px;
  font-weight: 600;
  font-family: 'Roboto', sans-serif;
}

.search-wrap {
  display: flex;
  justify-content: flex-end;
}

.search-input {
  width: 100%;
  max-width: 220px;
  padding: 8px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 0.95rem;
}

.fx-input {
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 1rem;
  background: #1d2630;
  color: #f8f8f8;
}

.calc-keypad {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 10px;
}

.calc-mini-controls {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-bottom: 10px;
}

.ad-slot {
  border: 1px dashed var(--border);
  background: #f9fafb;
  color: var(--muted);
  display: grid;
  place-items: center;
  font-size: 0.9rem;
  min-height: 70px;
}

.hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 30px;
  padding: 50px 6vw 30px;
}

.hero h1 {
  font-family: 'Merriweather', serif;
  font-size: 2.6rem;
  margin-bottom: 12px;
}

.hero p {
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 600px;
}

.calc-page {
  padding: 40px 6vw;
}

.category-section {
  padding: 30px 6vw;
}

.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 14px;
}

.category-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  display: grid;
  gap: 2px;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.category-card:hover {
  border-color: #a9b7c6;
  color: var(--accent);
}

.category-card.is-hidden {
  display: none;
}

.category-card h3 {
  margin: 0;
  color: var(--accent);
  font-size: 1.02rem;
}

.category-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.page-header h2 {
  font-size: 1.9rem;
  margin-bottom: 6px;
  color: var(--accent);
}

.page-header p {
  color: var(--muted);
  margin-top: 0;
}

.calc-layout {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: 24px;
  align-items: start;
}

.calculator,
.simple-calc,
.form-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
  padding: 20px;
}


.display {
  background: #1d2630;
  color: #f8f8f8;
  border-radius: 10px;
  padding: 12px 16px;
  margin-bottom: 16px;
  min-height: 70px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  font-variant-numeric: tabular-nums;
}

.display-expression {
  color: #a7b1bc;
  font-size: 0.95rem;
  min-height: 20px;
  word-break: break-all;
}

.display-result {
  font-size: 1.7rem;
  font-weight: 600;
  word-break: break-all;
}

.calc-controls {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  gap: 10px;
  margin-bottom: 12px;
}

.scicalc {
  display: grid;
  gap: 14px;
}

.scicalc-history {
  width: 100%;
  min-height: 90px;
  resize: none;
  border-radius: 8px;
  border: 1px solid var(--border);
  padding: 10px 12px;
  font-family: 'Source Sans 3', sans-serif;
  color: var(--muted);
  background: #f4f7fa;
}

.scicalc-display {
  background: #1d2630;
  border-radius: 10px;
  padding: 12px 16px;
  display: grid;
  gap: 6px;
}

.scicalc-input {
  width: 100%;
  border: none;
  outline: none;
  background: transparent;
  color: #f8f8f8;
  font-size: 1.4rem;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.scicalc-live {
  text-align: right;
  color: #a7b1bc;
  font-size: 1rem;
  font-variant-numeric: tabular-nums;
}

.scicalc-grid {
  display: grid;
  gap: 10px;
}

.scicalc-row {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 10px;
}

.scicalc-row-4 {
  grid-template-columns: repeat(4, 1fr);
}

.scicalc-btn {
  border: 1px solid var(--border);
  background: var(--button);
  color: var(--text);
  padding: 10px;
  border-radius: 8px;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.08s ease, background 0.2s ease, box-shadow 0.2s ease;
  box-shadow: inset 0 -2px 0 rgba(0, 0, 0, 0.08);
}

.scicalc-btn:hover {
  background: var(--button-hover);
}

.scicalc-btn:active {
  transform: translateY(1px);
  box-shadow: inset 0 0 0 rgba(0, 0, 0, 0.08);
}

.scicalc-spacer {
  visibility: hidden;
}

.scicalc-fn {
  background: #f1efe9;
  border-color: #d7d0c3;
}

.scicalc-op {
  background: #dfe7f2;
  border-color: #c0cfdf;
  color: #234f7a;
  font-weight: 600;
}

.scicalc-eq {
  background: var(--accent);
  color: #fff;
  font-weight: 700;
}

.mode-toggle {
  grid-column: 1 / -1;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.mode-pill {
  background: var(--accent-soft);
  color: var(--accent);
  padding: 4px 10px;
  border-radius: 999px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.ghost-btn {
  border: 1px solid var(--border);
  background: transparent;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 0.85rem;
  cursor: pointer;
}

.button-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.button-grid.wide {
  grid-template-columns: repeat(6, 1fr);
}

.simple-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.btn {
  padding: 12px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--button);
  font-size: 1rem;
  cursor: pointer;
  transition: transform 0.08s ease, background 0.2s ease, box-shadow 0.2s ease;
  box-shadow: inset 0 -2px 0 rgba(0, 0, 0, 0.08);
}

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

.btn:active,
.btn.active {
  transform: translateY(1px);
  box-shadow: inset 0 0 0 rgba(0, 0, 0, 0.08);
}

.btn.op {
  background: #dfe7f2;
  border-color: #c0cfdf;
  color: #234f7a;
  font-weight: 600;
}

.btn.fn {
  background: #f1efe9;
  border-color: #d7d0c3;
}

.btn.equals {
  grid-column: span 2;
  background: var(--accent);
  color: white;
  font-weight: 700;
}

.btn.primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.btn.primary:hover {
  background: #183d60;
}

.sidebar {
  position: sticky;
  top: 90px;
}

.inline-ad {
  margin-top: 20px;
  min-height: 90px;
}

.form-card {
  display: grid;
  gap: 12px;
  max-width: 520px;
}

.form-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.form-grid .form-card {
  max-width: none;
}

.pill-select {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.pill-select select,
.pill-select input {
  min-width: 140px;
}

.form-card label {
  display: grid;
  gap: 6px;
  font-weight: 600;
}

.form-card input {
  padding: 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 1rem;
}

.result-box {
  background: #f4f7fa;
  border: 1px solid var(--border);
  padding: 12px;
  border-radius: 8px;
  color: var(--muted);
}

.date-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.site-footer {
  padding: 24px 6vw 40px;
  border-top: 1px solid var(--border);
  background: var(--panel);
  display: grid;
  gap: 12px;
  text-align: center;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  font-weight: 600;
}

.footer-copy {
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 1024px) {
  .site-header {
    grid-template-columns: 1fr;
    justify-items: start;
  }

  .main-nav {
    flex-wrap: wrap;
  }

  .calc-layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }
}

@media (max-width: 768px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .button-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .button-grid.wide {
    grid-template-columns: repeat(4, 1fr);
  }

  .scicalc-grid {
    grid-template-columns: 1fr;
  }

  .scicalc-row {
    grid-template-columns: repeat(4, 1fr);
  }

  .calc-controls {
    grid-template-columns: repeat(2, 1fr);
  }

  .btn.equals {
    grid-column: span 2;
  }

  .site-header {
    padding: 16px 5vw;
  }

  .calc-page {
    padding: 32px 5vw;
  }
}