:root {
  color-scheme: dark;
  --bg: #030609;
  --panel: rgba(5, 10, 15, .88);
  --text: #f5f8f1;
  --muted: #7e8b93;
  --line: rgba(154, 182, 194, .22);
  --cyan: #4ce7ff;
  --acid: #d8ff3e;
  --mono: ui-monospace, "Cascadia Mono", "SFMono-Regular", Menlo, Consolas, monospace;
  --display: Impact, Haettenschweiler, "Arial Narrow Bold", sans-serif;
}

* { box-sizing: border-box; }

html, body { min-width: 320px; min-height: 100%; }

body {
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
}

#signal-field,
.scanlines {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

#signal-field { z-index: -2; }

.scanlines {
  z-index: 10;
  opacity: .22;
  background: repeating-linear-gradient(to bottom, transparent 0 3px, rgba(255,255,255,.025) 4px);
}

a { color: inherit; }

::selection { background: var(--acid); color: var(--bg); }

.topbar {
  display: grid;
  min-height: 72px;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 20px;
  padding: 14px clamp(18px, 4vw, 58px);
  border-bottom: 1px solid var(--line);
  background: rgba(3,6,9,.75);
  backdrop-filter: blur(12px);
}

.topbar a { text-decoration: none; }

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 9px;
  letter-spacing: .18em;
}

.brand > span {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--cyan);
  color: var(--cyan);
  font-family: var(--display);
  font-size: 20px;
}

.topbar p {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 0;
  color: var(--acid);
  font-size: 8px;
  font-weight: 800;
  letter-spacing: .2em;
}

.topbar p i {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--acid);
  box-shadow: 0 0 12px var(--acid);
}

.topbar > a:last-child {
  justify-self: end;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--cyan);
  font-size: 9px;
  font-weight: 800;
  letter-spacing: .18em;
}

main {
  display: grid;
  width: min(1360px, calc(100% - 36px));
  min-height: calc(100vh - 138px);
  grid-template-columns: minmax(300px, .8fr) minmax(400px, 1.2fr);
  grid-template-rows: 1fr auto;
  gap: clamp(28px, 7vw, 100px);
  align-items: center;
  margin: 0 auto;
  padding: clamp(70px, 9vw, 130px) 0 55px;
}

.intro { max-width: 630px; }

.kicker,
.field label,
.field legend,
.readout span,
footer {
  color: var(--muted);
  font-size: 8px;
  font-weight: 800;
  letter-spacing: .22em;
}

.intro h1 {
  margin: 26px 0 0;
  font-family: var(--display);
  font-size: clamp(58px, 8vw, 118px);
  font-style: italic;
  line-height: .82;
  letter-spacing: -.02em;
}

.intro h1 em { color: var(--acid); font-style: inherit; text-shadow: 7px 7px 0 rgba(76,231,255,.14); }

.intro > p:last-child {
  max-width: 520px;
  margin: 30px 0 0;
  color: #9ba7ad;
  font-size: 12px;
  line-height: 1.8;
}

.decoder {
  border: 1px solid var(--line);
  background: var(--panel);
  box-shadow: 0 30px 100px rgba(0,0,0,.35);
}

.decoder::before {
  display: block;
  height: 6px;
  background: repeating-linear-gradient(90deg, var(--cyan) 0 22px, transparent 22px 30px);
  content: "";
}

.field {
  display: block;
  margin: 0;
  padding: 24px;
  border: 0;
  border-bottom: 1px solid var(--line);
}

.field > div { margin-top: 15px; }

.message-field > div,
.frequency-field > div {
  display: flex;
  align-items: center;
  gap: 18px;
}

input[type="text"],
input:not([type]) {
  min-width: 0;
}

#message {
  width: 100%;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text);
  font: 700 clamp(16px, 2.2vw, 26px)/1.3 var(--mono);
  text-transform: uppercase;
}

#character-count,
#frequency-output {
  flex: none;
  color: var(--cyan);
  font-size: 9px;
  letter-spacing: .1em;
}

#frequency {
  width: 100%;
  height: 3px;
  margin: 12px 0;
  appearance: none;
  background: linear-gradient(90deg, var(--acid) var(--range-fill, 37.5%), rgba(126,139,147,.25) var(--range-fill, 37.5%));
}

#frequency::-webkit-slider-thumb {
  width: 18px;
  height: 18px;
  appearance: none;
  border: 3px solid var(--bg);
  border-radius: 0;
  background: var(--acid);
  box-shadow: 0 0 0 1px var(--acid);
  cursor: ew-resize;
}

#frequency::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border: 3px solid var(--bg);
  border-radius: 0;
  background: var(--acid);
  box-shadow: 0 0 0 1px var(--acid);
  cursor: ew-resize;
}

.mode-field > div { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }

.mode-field label { cursor: pointer; }
.mode-field input { position: absolute; opacity: 0; }

.mode-field label span {
  display: grid;
  min-height: 42px;
  place-items: center;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 8px;
  font-weight: 800;
  letter-spacing: .16em;
}

.mode-field input:checked + span {
  border-color: var(--cyan);
  background: rgba(76,231,255,.08);
  color: var(--cyan);
}

.mode-field input:focus-visible + span { outline: 2px solid var(--acid); outline-offset: 2px; }

.actions { display: grid; grid-template-columns: 1fr auto; gap: 10px; padding: 14px; }

.actions button {
  min-height: 50px;
  border: 0;
  font: 900 8px/1 var(--mono);
  letter-spacing: .18em;
  cursor: pointer;
}

.decode {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 18px;
  background: var(--acid);
  color: var(--bg);
}

.copy { padding: 0 20px; border: 1px solid var(--line) !important; background: transparent; color: var(--text); }

.actions button:hover { filter: brightness(1.13); }
.actions button:focus-visible { outline: 2px solid var(--cyan); outline-offset: 2px; }

.readout {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: auto 1fr auto 1fr;
  gap: 14px;
  align-items: center;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.readout strong { color: var(--cyan); font-size: 9px; letter-spacing: .12em; }

footer {
  display: flex;
  min-height: 66px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 18px clamp(18px, 4vw, 58px);
  border-top: 1px solid var(--line);
}

@media (max-width: 820px) {
  .topbar { grid-template-columns: 1fr auto; }
  .topbar p { display: none; }
  main { grid-template-columns: 1fr; grid-template-rows: auto; gap: 48px; }
  .readout { grid-column: auto; }
}

@media (max-width: 520px) {
  .brand strong { display: none; }
  main { width: min(100% - 24px, 1360px); padding-top: 58px; }
  .intro h1 { font-size: clamp(54px, 19vw, 78px); }
  .message-field > div, .frequency-field > div { align-items: flex-start; flex-direction: column; }
  .actions { grid-template-columns: 1fr; }
  .copy { min-height: 42px !important; }
  .readout { grid-template-columns: auto 1fr; }
  footer { align-items: flex-start; flex-direction: column; }
}

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