/* File: style.css */

/* ---- Base ---- */
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  line-height: 1.5;
  background: #0b1220;
  color: #e8eefc;
}

a { color: inherit; }
h1, h2, h3 { line-height: 1.2; margin: 0 0 12px; }
p { margin: 0 0 12px; }

.wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 28px 16px 56px;
}

/* ---- Hero ---- */
.hero { margin-bottom: 18px; }
.kicker {
  display: inline-block;
  font-size: 12px;
  letter-spacing: .12em;
  text-transform: uppercase;
  opacity: .8;
  margin: 0 0 10px;
}
.sub { opacity: .9; max-width: 62ch; }

/* ---- Cards ---- */
.card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.10);
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.25);
  margin: 14px 0;
}

/* ---- Form ---- */
.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 14px;
}

.field label {
  display: block;
  font-size: 13px;
  opacity: .9;
  margin-bottom: 6px;
}

.field input {
  width: 100%;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid rgba(255,255,255,0.16);
  background: rgba(255,255,255,0.06);
  color: #e8eefc;
  outline: none;
}

.field input::placeholder { opacity: .55; }
.field input:focus {
  border-color: rgba(120,170,255,0.65);
  box-shadow: 0 0 0 3px rgba(120,170,255,0.18);
}

.actions {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 4px;
}

button {
  appearance: none;
  border: 0;
  cursor: pointer;
  padding: 10px 14px;
  border-radius: 10px;
  font-weight: 700;
  background: #7bb0ff;
  color: #071023;
}

button:hover { filter: brightness(1.05); }
button:active { transform: translateY(1px); }

.hint { font-size: 13px; opacity: .8; margin: 0; }
.muted { opacity: .75; }

/* ---- Result ---- */
.result {
  border-top: 1px solid rgba(255,255,255,0.10);
  padding-top: 14px;
}

.result h3 { margin-top: 0; }
.result p { margin: 0 0 10px; }

details {
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid rgba(255,255,255,0.10);
  background: rgba(0,0,0,0.12);
}
summary { cursor: pointer; font-weight: 700; }

/* ---- Equation block ---- */
.method { margin-top: 12px; }

.method .equation {
  background: rgba(0,0,0,0.25);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 10px;
  padding: 10px 12px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
  overflow-x: auto;
}

.method .note {
  font-size: 13px;
  opacity: 0.8;
}

/* Utility */
.hidden { display: none; }

/* ---- Footer ---- */
.footer { margin-top: 18px; }

/* ---- Responsive ---- */
@media (max-width: 680px) {
  .grid { grid-template-columns: 1fr; }
}