:root {
  --navy: #001725;
  --panel: #002338;
  --blue-dark: #005184;
  --blue: #007ab7;
  --blue-light: #34A9E3;
  --pink: #f088e9;
  --white: #ffffff;
  --mono: Consolas, "Courier New", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background-color: var(--navy);
  color: var(--white);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.55;
}

a { color: var(--blue-light); }
a:hover { color: var(--pink); }

header {
  padding: 40px 20px 24px;
  text-align: center;
  background-color: var(--blue-dark);
  border-bottom: 4px solid var(--pink);
}

header h1 {
  margin: 0;
  font-size: 2.6rem;
  letter-spacing: 1px;
}

.tagline { margin: 8px 0 18px; font-size: 1.1rem; }

nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}

nav a {
  padding: 6px 14px;
  border: 2px solid var(--white);
  color: var(--white);
  text-decoration: none;
}

nav a:hover { background-color: var(--white); color: var(--blue-dark); }

main {
  max-width: 980px;
  margin: 0 auto;
  padding: 10px 16px 40px;
}

section { padding-top: 24px; }

h2 {
  color: var(--blue-light);
  border-bottom: 2px solid var(--blue-dark);
  padding-bottom: 6px;
}

h3 { margin: 0 0 10px; color: var(--pink); }

.panel {
  background-color: var(--panel);
  border: 2px solid var(--blue-dark);
  padding: 16px;
  margin: 14px 0;
}

.panel-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.file { font-family: var(--mono); color: var(--blue-light); }

#progress { margin: 8px 0; font-weight: bold; }

.picker {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(56px, 1fr));
  gap: 6px;
}

.picker button {
  padding: 10px 0;
  font-size: 1rem;
  font-family: var(--mono);
  background-color: var(--navy);
  color: var(--white);
  border: 2px solid var(--blue);
  cursor: pointer;
}

.picker button:hover { background-color: var(--blue-dark); }
.picker button.solved { background-color: var(--pink); border-color: var(--pink); color: var(--navy); }
.picker button.current { border-color: var(--white); outline: 2px solid var(--white); }

.code {
  margin: 10px 0;
  padding: 12px;
  max-height: 220px;
  overflow: auto;
  background-color: var(--navy);
  border: 1px solid var(--blue-dark);
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--blue-light);
  white-space: pre-wrap;
  word-break: break-all;
}

.code .pc { background-color: var(--pink); color: var(--navy); }

.btn {
  padding: 9px 16px;
  margin: 4px 4px 4px 0;
  font-size: 1rem;
  background-color: var(--blue);
  color: var(--white);
  border: 2px solid var(--blue-light);
  cursor: pointer;
}

.btn:hover { background-color: var(--blue-light); }
.btn.ghost { background-color: transparent; }
.btn.ghost:hover { background-color: var(--blue-dark); }
.btn:disabled { opacity: 0.5; cursor: default; }

.link {
  background: none;
  border: none;
  padding: 0;
  color: var(--blue-light);
  text-decoration: underline;
  cursor: pointer;
  font-size: inherit;
}

.runbar { display: flex; flex-wrap: wrap; align-items: center; gap: 4px; }

.speed { margin-left: 8px; }

.tape {
  display: flex;
  gap: 4px;
  margin: 10px 0;
  overflow-x: auto;
  font-family: var(--mono);
}

.cell {
  min-width: 52px;
  padding: 4px;
  text-align: center;
  border: 1px solid var(--blue-dark);
  background-color: var(--navy);
}

.cell small { display: block; color: var(--blue-light); font-size: 0.7rem; }
.cell.ptr { border-color: var(--pink); color: var(--pink); }

.output {
  min-height: 3em;
  padding: 12px;
  background-color: var(--white);
  color: var(--navy);
  font-size: 1.15rem;
  white-space: pre-wrap;
  word-break: break-word;
}

.answer { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 12px; }

input[type="text"], textarea {
  padding: 9px 10px;
  font-size: 1rem;
  background-color: var(--navy);
  color: var(--white);
  border: 2px solid var(--blue);
}

#answer { flex: 1 1 200px; }

textarea { width: 100%; font-family: var(--mono); resize: vertical; }

.field { display: block; margin: 8px 0; }
.field input { width: 100%; margin-top: 4px; }

.verdict { min-height: 1.6em; margin-top: 8px; font-weight: bold; }
.verdict.good { color: var(--pink); }
.verdict.bad { color: var(--blue-light); }

.nav-riddles { display: flex; justify-content: space-between; margin-top: 8px; }

.cols { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.cols .panel { margin: 0; min-width: 0; }

.small { font-size: 0.9rem; }

code { font-family: var(--mono); color: var(--pink); }

footer {
  padding: 24px 16px;
  text-align: center;
  background-color: var(--blue-dark);
  border-top: 4px solid var(--pink);
}

footer p { margin: 4px 0; }
footer a { color: var(--white); }

@media (max-width: 720px) {
  header h1 { font-size: 2rem; }
  .cols { grid-template-columns: 1fr; }
  .speed { margin-left: 0; width: 100%; }
}