@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600&family=Space+Grotesk:wght@400;500;600;700&display=swap");

:root {
  --bg: #0d0f14;
  --bg-deep: #0a0c11;
  --panel: #171a23;
  --panel-strong: #202433;
  --text: #f2f4f8;
  --text-muted: #b7bfcc;
  --accent: #ffbe3c;
  --accent-strong: #ff9f1c;
  --accent-cool: #6cd0ff;
  --stroke: rgba(255, 255, 255, 0.08);
  --shadow: rgba(0, 0, 0, 0.45);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: radial-gradient(800px circle at 8% -10%, rgba(255, 190, 60, 0.18), transparent 60%),
    radial-gradient(700px circle at 95% 10%, rgba(108, 208, 255, 0.2), transparent 58%),
    linear-gradient(180deg, var(--bg), #121620 55%, var(--bg-deep));
  color: var(--text);
  font-family: "IBM Plex Sans", "Space Grotesk", sans-serif;
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background: radial-gradient(2px 2px at 20% 30%, rgba(255, 255, 255, 0.12), transparent 50%),
    radial-gradient(1px 1px at 70% 60%, rgba(255, 255, 255, 0.08), transparent 40%),
    radial-gradient(2px 2px at 85% 20%, rgba(255, 255, 255, 0.06), transparent 50%);
  pointer-events: none;
  opacity: 0.5;
  z-index: 0;
}

.page {
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 0 auto;
  padding: 56px 20px 80px;
  display: grid;
  gap: 28px;
}

.hero {
  display: grid;
  gap: 12px;
  animation: floatIn 0.8s ease both;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-size: 12px;
  color: var(--text-muted);
}

h1 {
  margin: 0;
  font-family: "Space Grotesk", sans-serif;
  font-size: clamp(2.2rem, 4vw, 3.2rem);
  line-height: 1.05;
}

.sub {
  margin: 0;
  color: var(--text-muted);
  max-width: 720px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--stroke);
  border-radius: 18px;
  padding: 24px;
  box-shadow: 0 30px 60px var(--shadow);
  animation: rise 0.7s ease both;
}

.card h2 {
  margin: 0 0 18px;
  font-family: "Space Grotesk", sans-serif;
  font-size: 1.4rem;
}

.input-card {
  display: grid;
  gap: 18px;
  padding-top: 18px;
}


.mode-section {
  display: grid;
  gap: 16px;
}

.class-section {
  display: grid;
  gap: 16px;
}

.class-section.is-hidden {
  display: none;
}

.section-title {
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-top: 6px;
}

.field {
  display: grid;
  gap: 10px;
}

.label-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

label {
  font-weight: 600;
}

input[type="number"] {
  background: var(--panel-strong);
  border: 1px solid var(--stroke);
  border-radius: 12px;
  color: var(--text);
  font-size: 1rem;
  padding: 12px 14px;
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

select {
  background: var(--panel-strong);
  border: 1px solid var(--stroke);
  border-radius: 12px;
  color: var(--text);
  font-size: 1rem;
  padding: 12px 14px;
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

select:focus {
  border-color: rgba(255, 190, 60, 0.7);
  box-shadow: 0 0 0 3px rgba(255, 190, 60, 0.15);
}

input[type="number"]:focus {
  border-color: rgba(255, 190, 60, 0.7);
  box-shadow: 0 0 0 3px rgba(255, 190, 60, 0.15);
}

input::placeholder {
  color: rgba(183, 191, 204, 0.6);
}

.field-hint {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.segmented {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
  background: var(--panel-strong);
  border-radius: 14px;
  border: 1px solid var(--stroke);
  overflow: hidden;
}

.seg-item {
  position: relative;
  cursor: pointer;
}

.seg-item input {
  position: absolute;
  opacity: 0;
}

.seg-item span {
  display: block;
  text-align: center;
  padding: 12px 14px;
  color: var(--text-muted);
  font-weight: 600;
  transition: all 0.2s ease;
}

.seg-item input:checked + span {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: #1a1206;
}

.segmented--three {
  grid-template-columns: repeat(3, 1fr);
}

.check-row {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  font-weight: 600;
}

.check-row input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

.pill {
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(108, 208, 255, 0.2);
  color: var(--accent-cool);
  letter-spacing: 0.08em;
}

.notes {
  display: grid;
  gap: 10px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.result-card {
  display: grid;
  gap: 20px;
  padding-top: 18px;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.stat {
  background: var(--panel-strong);
  border-radius: 14px;
  padding: 16px;
  border: 1px solid var(--stroke);
}

.label {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.value {
  font-size: 1.6rem;
  font-weight: 700;
  margin-top: 6px;
  font-family: "Space Grotesk", sans-serif;
}

.muted {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.progress {
  position: relative;
  height: 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--accent-cool));
  transition: width 0.3s ease;
}

.progress-text {
  margin-top: 8px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.split {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
}

.breakpoints {
  display: grid;
  gap: 12px;
  padding: 16px;
  border-radius: 14px;
  border: 1px solid var(--stroke);
  background: rgba(20, 23, 32, 0.8);
}

.breakpoints-header {
  display: grid;
  gap: 4px;
}

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

.breakpoint {
  padding: 12px;
  border-radius: 12px;
  border: 1px solid var(--stroke);
  background: var(--panel-strong);
}

.mini {
  padding: 14px;
  border-radius: 12px;
  border: 1px solid var(--stroke);
  background: rgba(20, 23, 32, 0.8);
}

.mini.wide {
  grid-column: 1 / -1;
}

.callouts {
  display: grid;
  gap: 10px;
  padding: 14px;
  border-radius: 12px;
  background: rgba(255, 190, 60, 0.08);
  border: 1px solid rgba(255, 190, 60, 0.25);
  color: #fdd98c;
  font-weight: 500;
}

.callouts p {
  margin: 0;
}

.info-card {
  display: grid;
  gap: 16px;
  animation: rise 0.9s ease both;
}

.formula {
  display: grid;
  gap: 10px;
  background: var(--panel-strong);
  padding: 16px;
  border-radius: 12px;
  border: 1px solid var(--stroke);
  font-family: "IBM Plex Sans", sans-serif;
  font-size: 0.95rem;
}

.formula code {
  display: block;
  color: var(--text);
}

.legend {
  display: grid;
  gap: 6px;
  color: var(--text-muted);
}

@keyframes floatIn {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 720px) {
  .page {
    padding: 40px 16px 64px;
  }

  .card {
    padding: 20px;
  }

  .value {
    font-size: 1.4rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}