@font-face {
  font-family: "Fixel Text";
  src: url("fonts/FixelText-Regular.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
}

@font-face {
  font-family: "Fixel Text";
  src: url("fonts/FixelText-SemiBold.woff2") format("woff2");
  font-weight: 600;
  font-display: swap;
}

@font-face {
  font-family: "Fixel Display";
  src: url("fonts/FixelDisplay-Bold.woff2") format("woff2");
  font-weight: 700;
  font-display: swap;
}

@font-face {
  font-family: "IBM Plex Mono";
  src: url("fonts/IBMPlexMono-400-latin.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: "IBM Plex Mono";
  src: url("fonts/IBMPlexMono-400-cyrillic.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}

/*
  Palette. Colour comes only from the two brand sources: the Ukrainian flag
  (#0057b7, #ffd700) and the C++ logo, whose blue has the same hue (~210deg).
  Everything else is neutral grey, so there is no tinted "default" dark theme.
  Flag blue is too dark for text on a dark background (~2.7:1), so it is used
  for fills only; links use a lighter tint of the same hue.
*/
:root {
  --bg: #131313;
  --surface: #1b1b1b;
  --border: #2b2b2b;
  --border-strong: #666666;
  --text: #f4f4f4;
  --muted: #a3a3a3;
  --link: #6aa6ec;
  --blue: #0057b7;
  --yellow: #ffd700;
  --cta-bg: var(--yellow);
  --cta-fg: #131313;
  --cta-hover: #ffe24d;
  --code-bg: #0d0d0d;
  --code-border: var(--border);
  --code-text: #e6e6e6;
  --code-muted: #8a8a8a;
  --code-kw: #6aa6ec;
  --code-str: var(--yellow);

  --sans: "Fixel Text", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --display: "Fixel Display", "Fixel Text", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --max: 1080px;
  --radius: 12px;
  color-scheme: dark;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, p {
  margin: 0;
}

a {
  color: var(--link);
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--text);
}

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

:focus-visible {
  outline: 2px solid var(--yellow);
  outline-offset: 3px;
  border-radius: 4px;
}

.nowrap {
  white-space: nowrap;
}

.container {
  max-width: var(--max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.sprite {
  position: absolute;
  width: 0;
  height: 0;
}

.icon {
  width: 1.15em;
  height: 1.15em;
  flex: none;
}

/* Support banner in the page's own surface colour; the flag is the only
   colour in it, as on macpaw.com and preply.com. */
.banner {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 4px 10px;
  padding: 9px 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  font-size: 0.875rem;
  text-align: center;
}

.banner-flag {
  flex: none;
  width: 18px;
  height: 12px;
  border-radius: 2px;
  background: linear-gradient(var(--blue) 50%, var(--yellow) 50%);
}

.banner a {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-weight: 600;
  text-decoration: none;
}

.banner a .icon {
  width: 1em;
  height: 1em;
}

/* Header */

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 32px;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 20px;
}

.header-link,
.lang-switch {
  color: var(--muted);
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
  text-decoration: none;
}

.lang-switch {
  padding: 4px 8px;
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
}

.header-link:hover,
.lang-switch:hover {
  color: var(--text);
}

/* Logo: cpp::ua, where :: are two blue-over-yellow colons */

.logo {
  display: inline-flex;
  align-items: baseline;
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.7rem;
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--text);
  text-decoration: none;
}

.logo:hover {
  color: var(--text);
}

/* Dots are absolutely positioned so the box has no baseline of its own:
   its bottom edge then sits on the text baseline, like a real colon. */
.logo-sep {
  position: relative;
  display: inline-block;
  width: 0.53em;
  height: 0.47em;
  margin: 0 0.08em 0 0.1em;
}

.logo-sep i {
  position: absolute;
  width: 0.2em;
  height: 0.2em;
  border-radius: 50%;
  background: var(--blue);
}

.logo-sep i:nth-child(1) { left: 0; top: 0; }
.logo-sep i:nth-child(2) { right: 0; top: 0; }
.logo-sep i:nth-child(3) { left: 0; bottom: 0; background: var(--yellow); }
.logo-sep i:nth-child(4) { right: 0; bottom: 0; background: var(--yellow); }

.logo-small {
  font-size: 1.35rem;
}

/* Hero */

.hero {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 56px;
  align-items: center;
  padding-top: 88px;
  padding-bottom: 48px;
}

h1 {
  font-family: var(--display);
  font-size: clamp(2.3rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.lead {
  margin-top: 22px;
  max-width: 32em;
  font-size: 1.15rem;
  color: var(--muted);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 22px;
  border-radius: 10px;
  border: 1px solid transparent;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  transition: background-color 0.15s, border-color 0.15s;
}

.btn-primary {
  background: var(--cta-bg);
  color: var(--cta-fg);
}

.btn-primary:hover {
  background: var(--cta-hover);
  color: var(--cta-fg);
}

.btn-secondary {
  border-color: var(--border-strong);
  color: var(--text);
}

.btn-secondary:hover {
  background: var(--surface);
  color: var(--text);
}

/* The business card itself, written as C++ */

.card-code {
  margin: 0;
  min-width: 0;
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius);
  overflow: hidden;
}

.card-code figcaption {
  padding: 11px 20px;
  border-bottom: 1px solid var(--code-border);
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--code-muted);
}

.card-code pre {
  margin: 0;
  padding: 22px 20px 24px;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--code-text);
}

.card-code .kw { color: var(--code-kw); }
.card-code .fld { color: var(--code-muted); }
.card-code .str { color: var(--code-str); }

/* A faint underline tells links apart from plain strings like the name */
.card-code a.str {
  text-decoration: underline;
  text-decoration-color: rgb(255 215 0 / 0.35);
  text-underline-offset: 0.25em;
}

.card-code a.str:hover {
  text-decoration-color: currentColor;
  color: var(--code-str);
}

/* Sections */

.block {
  padding-top: 72px;
  padding-bottom: 8px;
}

.block + .block {
  padding-top: 88px;
}

h2 {
  font-family: var(--display);
  font-size: clamp(1.7rem, 3vw, 2.1rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.block-lead {
  margin-top: 12px;
  max-width: 40em;
  color: var(--muted);
}

h3 {
  font-size: 1.1rem;
  font-weight: 600;
  line-height: 1.35;
}

.columns {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 36px;
  margin-top: 36px;
}

.column {
  padding-top: 18px;
  border-top: 3px solid var(--border);
}

.column:first-child {
  border-top-color: var(--blue);
}

.column:nth-child(2) {
  border-top-color: var(--yellow);
}

.column p,
.card p {
  margin-top: 8px;
  color: var(--muted);
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 32px;
}

.card {
  display: flex;
  flex-direction: column;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.card p {
  flex: 1;
  font-size: 0.97rem;
}

.card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 18px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
}

/* Text pages: rules and 404 */

.page {
  padding-top: 88px;
}

.page h1 {
  font-size: clamp(2.1rem, 4.5vw, 2.9rem);
}

.page-kicker {
  margin-bottom: 16px;
  font-family: var(--mono);
  font-size: 0.9rem;
  color: var(--yellow);
}

.rules {
  max-width: 40em;
  margin: 40px 0 0;
  padding-left: 1.8em;
}

.rules li {
  padding-left: 0.5em;
}

.rules li + li {
  margin-top: 16px;
}

.rules li::marker {
  font-family: var(--mono);
  font-size: 0.9em;
  color: var(--muted);
}

.page-note {
  max-width: 40em;
  margin-top: 40px;
  color: var(--muted);
}

/* Footer */

.footer {
  margin-top: 104px;
  border-top: 1px solid var(--border);
}

.footer-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px 32px;
  padding-top: 28px;
  padding-bottom: 40px;
}

.footer-brand {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 4px 16px;
  color: var(--muted);
  font-size: 0.92rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-links a {
  color: var(--muted);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--text);
}

/* Responsive */

@media (max-width: 880px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 44px;
    padding-top: 56px;
    padding-bottom: 40px;
  }

  .columns,
  .cards {
    grid-template-columns: 1fr;
  }

  .columns {
    gap: 28px;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 16px;
  }

  .container {
    padding-left: 16px;
    padding-right: 16px;
  }

  .header {
    padding-top: 24px;
  }

  .logo {
    font-size: 1.5rem;
  }

  .header-nav {
    gap: 12px;
  }

  .header-link {
    font-size: 0.875rem;
  }

  .actions .btn {
    flex: 1 1 auto;
    justify-content: center;
  }

  .card-code pre {
    font-size: 0.8rem;
    padding: 18px 16px 20px;
  }

  .block {
    padding-top: 56px;
  }

  .block + .block {
    padding-top: 64px;
  }

  .page {
    padding-top: 56px;
  }

  .footer {
    margin-top: 72px;
  }
}

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