@import url("https://fonts.googleapis.com/css2?family=Shippori+Antique+B1&display=swap");

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type="number"] {
  -moz-appearance: textfield;
  appearance: textfield;
}

:root {
  --labels-size: 1rem;
  --primary-color: aliceblue;
  --secondary-color: darkblue;
  --surface: rgba(255, 255, 255, 0.16);
  --surface-strong: rgba(255, 255, 255, 0.9);
  --surface-border: rgba(255, 255, 255, 0.25);
  --text-main: #f7fbff;
  --text-soft: rgba(247, 251, 255, 0.82);
  --shadow: 0 24px 60px rgba(3, 18, 54, 0.28);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Shippori Antique B1", Arial, Helvetica, sans-serif;
}

body {
  min-height: 100vh;
  color: var(--text-main);
  background:
    radial-gradient(circle at top left, rgba(110, 245, 255, 0.18), transparent 28%),
    radial-gradient(circle at bottom right, rgba(54, 98, 255, 0.2), transparent 32%),
    linear-gradient(135deg, #061225 0%, #0e2a4e 48%, #113a63 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
  background-size: 42px 42px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.6), transparent 90%);
}

.container {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 40px;
  display: grid;
  gap: 20px;
}

.hero,
.main-shell,
.box-3,
.formula-card {
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.hero {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 24px 28px;
  border: 1px solid var(--surface-border);
  border-radius: 24px;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.17), rgba(255, 255, 255, 0.08));
  box-shadow: var(--shadow);
}

.hero-copy h1 {
  font-size: clamp(2rem, 4vw, 3.4rem);
  line-height: 1.05;
  margin-top: 6px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.78rem;
  color: #bde9ff;
}

.subtitle {
  margin-top: 10px;
  max-width: 56ch;
  color: var(--text-soft);
  font-size: 1rem;
}

.hero-actions {
  flex-shrink: 0;
}

.home-btn {
  min-width: 168px;
}

.main-shell {
  display: grid;
  gap: 18px;
  padding: 22px;
  border: 1px solid var(--surface-border);
  border-radius: 28px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0.08));
  box-shadow: var(--shadow);
}

.box-1 {
  display: none;
}

.tool-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(280px, 0.9fr);
  gap: 18px;
}

.box-2 {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-content: flex-start;
}

.formula-card {
  border-radius: 22px;
  padding: 18px 20px;
  border: 1px solid var(--surface-border);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.16), rgba(255, 255, 255, 0.09));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.22);
}

.formula-label {
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-size: 0.76rem;
  color: #b9ddff;
}

.formula-text {
  margin-top: 10px;
  font-size: clamp(1.35rem, 3vw, 2rem);
  line-height: 1.2;
  font-weight: 700;
}

.formula-note {
  margin-top: 10px;
  color: var(--text-soft);
  line-height: 1.6;
}

.btn {
  text-transform: uppercase;
  text-align: center;
  padding: 0.9rem 1.05rem;
  border-radius: 999px;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 160ms ease, box-shadow 160ms ease, background-color 160ms ease, color 160ms ease, border-color 160ms ease;
}

.opt-btn {
  flex: 1 1 190px;
  min-height: 52px;
  background: rgba(255, 255, 255, 0.9);
  color: #153e7a;
  box-shadow: 0 10px 24px rgba(4, 18, 46, 0.16);
}

.btn:hover,
.btn:focus-visible,
.selected {
  background: #103f86;
  color: #f4fbff;
  border-color: rgba(255, 255, 255, 0.18);
  box-shadow: 0 14px 32px rgba(6, 21, 52, 0.28);
}

.selected {
  transform: translateY(-1px);
  box-shadow:
    0 0 0 3px rgba(171, 236, 255, 0.42),
    0 14px 32px rgba(6, 21, 52, 0.3);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:focus-visible {
  outline: 3px solid rgba(172, 237, 255, 0.65);
  outline-offset: 2px;
}

.home-btn {
  background: rgba(255, 255, 255, 0.18);
  color: var(--text-main);
  border-color: rgba(255, 255, 255, 0.2);
  padding-inline: 1.2rem;
}

.home-btn:hover,
.home-btn:focus-visible {
  background: rgba(255, 255, 255, 0.92);
  color: #12366a;
}

.box-3 {
  display: grid;
  grid-template-columns: auto 1fr auto;
  column-gap: 1rem;
  row-gap: 1rem;
  padding: 22px;
  border-radius: 24px;
  border: 1px solid var(--surface-border);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(245, 250, 255, 0.9));
  color: #08213d;
  box-shadow: var(--shadow);
}

.selection {
  grid-column: 1 / -1;
}

.helper-text {
  grid-column: 1 / -1;
  margin-top: -0.25rem;
  color: #516b86;
  font-size: 0.9rem;
}

.choose-legend {
  display: inline-block;
  margin-bottom: 0.6rem;
  color: #16426f;
  font-size: var(--labels-size);
}

.ddMenu {
  width: min(100%, 360px);
  padding: 0.85rem 1rem;
  font-size: 1rem;
  cursor: pointer;
  background-color: #f7fbff;
  color: #12335f;
  border: 1px solid rgba(18, 51, 95, 0.18);
  border-radius: 14px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7);
}

.message {
  grid-column: 1 / -1;
  padding: 0.8rem 0.95rem;
  border-radius: 14px;
  background: linear-gradient(180deg, rgba(254, 248, 240, 0.98), rgba(255, 241, 241, 0.98));
  color: #842c2c;
  border: 1px solid rgba(132, 44, 44, 0.14);
  font-size: 0.95rem;
  line-height: 1.5;
}

.label {
  display: flex;
  align-items: center;
  min-height: 52px;
  color: #103760;
  font-weight: 700;
}

.input {
  width: 100%;
  min-height: 52px;
  padding: 0.75rem 0.9rem;
  border: 1px solid rgba(16, 55, 96, 0.18);
  font-size: 1rem;
  background: #f9fcff;
  color: #0f2f54;
  border-radius: 14px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

.input:focus {
  outline: none;
  border-color: rgba(17, 68, 138, 0.45);
  box-shadow: 0 0 0 4px rgba(54, 123, 255, 0.14);
}

.input.result {
  background: linear-gradient(180deg, #e8f7ed, #d8efd9);
  border-color: rgba(43, 121, 63, 0.22);
  font-weight: 700;
  color: #13491f;
}

.lbl-unit {
  display: flex;
  align-items: center;
  min-height: 52px;
  color: #4f6785;
  font-size: 0.95rem;
  justify-self: start;
}

.box-3 > .label {
  grid-column: 1 / 2;
  justify-self: end;
}

.box-3 > .input {
  grid-column: 2 / 3;
}

.box-3 > .lbl-unit {
  grid-column: 3 / 4;
}

.author {
  font-size: 0.7em;
}

@media (max-width: 900px) {
  .tool-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .container {
    width: min(100% - 20px, 1120px);
    padding-top: 14px;
    gap: 16px;
  }

  .hero {
    flex-direction: column;
    align-items: flex-start;
    padding: 20px;
  }

  .hero-actions {
    width: 100%;
  }

  .home-btn {
    width: 100%;
    min-width: 0;
  }

  .main-shell {
    padding: 16px;
  }

  .box-2 {
    gap: 12px;
  }

  .opt-btn {
    flex-basis: 100%;
    min-height: 50px;
  }

  .box-3 {
    grid-template-columns: 1fr;
    row-gap: 0.8rem;
    padding: 16px;
  }

  .selection,
  .helper-text,
  .message,
  .box-3 > .label,
  .box-3 > .input,
  .box-3 > .lbl-unit {
    grid-column: 1 / -1;
    justify-self: stretch;
  }

  .label,
  .lbl-unit {
    min-height: auto;
  }

  .input,
  .ddMenu {
    width: 100%;
  }
}