:root {
  color-scheme: light dark;
  --bg: #f4f1e8;
  --panel: #fffaf0;
  --panel-strong: #202124;
  --text: #202124;
  --muted: #6e6a61;
  --line: #bbb3a0;
  --tile: #fffdf6;
  --tile-active: #202124;
  --tile-active-text: #fff8e5;
  --accent: #d94719;
  --warning-bg: #ffe2a8;
  --warning-text: #4b3000;
  --shadow: 0 16px 34px rgb(32 33 36 / 14%);
  --radius: 8px;
  --tap: 58px;
}

:root[data-theme="dark"] {
  --bg: #171717;
  --panel: #242321;
  --panel-strong: #f6efe0;
  --text: #f6efe0;
  --muted: #b8afa0;
  --line: #4f4a42;
  --tile: #1d1c1a;
  --tile-active: #f6efe0;
  --tile-active-text: #171717;
  --accent: #ff6a2a;
  --warning-bg: #573c10;
  --warning-text: #ffe2a8;
  --shadow: 0 18px 42px rgb(0 0 0 / 34%);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #171717;
    --panel: #242321;
    --panel-strong: #f6efe0;
    --text: #f6efe0;
    --muted: #b8afa0;
    --line: #4f4a42;
    --tile: #1d1c1a;
    --tile-active: #f6efe0;
    --tile-active-text: #171717;
    --accent: #ff6a2a;
    --warning-bg: #573c10;
    --warning-text: #ffe2a8;
    --shadow: 0 18px 42px rgb(0 0 0 / 34%);
  }
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--bg);
}

body {
  min-height: 100%;
  margin: 0;
  color: var(--text);
  background:
    linear-gradient(90deg, rgb(0 0 0 / 4%) 1px, transparent 1px) 0 0 / 28px 28px,
    var(--bg);
  font-family: "Segoe UI", "Noto Sans", Tahoma, sans-serif;
  letter-spacing: 0;
}

button,
input {
  font: inherit;
}

.app-shell {
  width: min(100%, 620px);
  min-height: 100svh;
  margin: 0 auto;
  padding: max(14px, env(safe-area-inset-top)) 14px 24px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 0 14px;
}

.result-label,
dt {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.2;
  text-transform: uppercase;
}

h1 {
  margin: 4px 0 0;
  font-size: clamp(20px, 5.8vw, 28px);
  line-height: .95;
  letter-spacing: 0;
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border: 2px solid var(--line);
  border-radius: 50%;
  color: var(--text);
  background: var(--panel);
  cursor: pointer;
}

.theme-toggle span {
  font-size: 22px;
  line-height: 1;
}

.theme-toggle:focus-visible,
.tile:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.result-panel {
  position: sticky;
  top: 8px;
  z-index: 2;
  display: grid;
  gap: 12px;
  margin-bottom: 18px;
  padding: 20px;
  border: 2px solid var(--panel-strong);
  border-radius: var(--radius);
  color: var(--tile-active-text);
  background: var(--panel-strong);
  box-shadow: var(--shadow);
}

.amp-result {
  display: block;
  font-size: clamp(48px, 15vw, 72px);
  font-weight: 900;
  line-height: .9;
  letter-spacing: 0;
}

.result-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(118px, 1fr));
  gap: 10px;
  margin: 0;
}

.result-meta div {
  min-width: 0;
}

.result-meta dt {
  color: color-mix(in srgb, var(--tile-active-text), transparent 35%);
}

.result-meta dd {
  margin: 3px 0 0;
  font-size: 18px;
  font-weight: 800;
}

.warning {
  margin: 0;
  padding: 11px 12px;
  border-left: 5px solid var(--accent);
  border-radius: 4px;
  color: var(--warning-text);
  background: var(--warning-bg);
  font-size: 16px;
  font-weight: 800;
  line-height: 1.25;
}

.calculator {
  display: grid;
  gap: 18px;
}

fieldset {
  min-width: 0;
  margin: 0;
  padding: 0;
  border: 0;
}

legend,
h2 {
  margin: 0 0 10px;
  color: var(--text);
  font-size: 22px;
  font-weight: 900;
  line-height: 1;
}

.tile-grid {
  display: grid;
  gap: 8px;
}

.electrode-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.metal-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.type-grid,
.position-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.tile {
  min-height: var(--tap);
  padding: 11px 8px;
  border: 2px solid var(--line);
  border-radius: var(--radius);
  color: var(--text);
  background: var(--tile);
  box-shadow: inset 0 -3px 0 rgb(0 0 0 / 7%);
  cursor: pointer;
}

.tile[aria-pressed="true"] {
  border-color: var(--tile-active);
  color: var(--tile-active-text);
  background: var(--tile-active);
}

.tile-main {
  display: block;
  font-size: 20px;
  font-weight: 900;
  line-height: 1.05;
}

.type-grid .tile-main {
  font-size: 17px;
}

.tile-sub {
  display: block;
  margin-top: 4px;
  color: inherit;
  font-size: 12px;
  font-weight: 800;
  opacity: .72;
}

.guidance {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 2px solid var(--line);
}

.practice-text,
.trouble-list {
  margin: 0;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--panel), transparent 18%);
  color: var(--muted);
  font-size: 15px;
  font-weight: 700;
  line-height: 1.35;
}

.trouble-list {
  display: grid;
  gap: 8px;
  padding-left: 30px;
}

.site-footer {
  display: grid;
  justify-items: center;
  gap: 10px;
  margin-top: 28px;
  padding: 20px 0 6px;
  border-top: 2px solid var(--line);
  text-align: center;
}

.footer-logo {
  width: min(50vw, 320px);
  min-width: 150px;
  height: auto;
}

.footer-logo-link,
.footer-domain {
  color: var(--text);
  text-decoration: none;
}

.footer-domain {
  font-size: 18px;
  font-weight: 900;
  line-height: 1.2;
}

.forum-link {
  display: inline-block;
  color: var(--text);
  font-size: 15px;
  font-weight: 800;
  line-height: 1.25;
  text-decoration: none;
}

.footer-logo-link:focus-visible,
.footer-domain:focus-visible,
.forum-link:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 5px;
}

.footer-logo-link:hover,
.footer-logo-link:focus-visible,
.footer-domain:hover,
.footer-domain:focus-visible,
.forum-link:hover,
.forum-link:focus-visible {
  color: var(--accent);
}

@media (max-width: 390px) {
  .app-shell {
    padding-inline: 10px;
  }

  .position-grid,
  .type-grid,
  .electrode-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .amp-result {
    font-size: 46px;
  }

  .result-meta {
    grid-template-columns: 1fr;
  }

  .type-grid .tile-main {
    font-size: 16px;
  }
}