/* Self-contained styling for the S_n arithmetic drills. */

:root {
  color-scheme: dark;
  --ink: #eaeaea;
  --muted: #b7bdc5;
  --panel: #1f242c;
  --line: #51555d;
  --accent: #00adb5;
  --focus: #8cd2d5;
  --success: #3fa63f;
  --error: #ee5f5b;
}

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

html {
  background: #252a34;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding: 0;
  color: var(--ink);
  background: #252a34;
  font-family: "XCharter Web", Charter, "Bitstream Charter", Georgia, serif;
  font-size: 1rem;
  line-height: 1.5;
}

main {
  display: block;
  max-width: 52rem;
  margin: 3rem auto;
  padding: 2rem 2.25rem 2.5rem;
}

h1, h2 {
  margin-top: 0;
  line-height: 1.2;
}

h1 {
  font-size: 1.953em;
}

h2 {
  margin-top: 2rem;
  font-size: 1.563em;
}

p {
  margin-top: 0;
  margin-bottom: 1.3em;
}

button,
input {
  margin: 0;
  font: inherit;
  vertical-align: middle;
}

button {
  cursor: pointer;
}

button:focus,
input:focus {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.btn {
  display: inline-block;
  padding: .5em 1em;
  border: 0;
  border-radius: 4px;
  font-weight: bold;
  text-align: center;
}

.btn--primary {
  color: #fff;
  background: var(--accent);
}

.btn--primary:hover,
.btn--primary:focus {
  background: #008a91;
}

.controls {
  display: inline-flex;
  padding: 1rem;
  background: var(--panel);
  border-radius: 4px;
}

.controls label {
  display: flex;
  flex-direction: column;
  gap: .2rem;
}

.controls input.input-mini {
  width: 4.5rem;
  margin-top: .2rem;
  padding: .25em .4em;
  color: var(--ink);
  background: #252a34;
  border: 1px solid var(--line);
  border-radius: 4px;
}

.drill + .drill {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

.new-problem {
  display: block;
  margin-top: .75rem;
}

.problem {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 2rem 0 1.4rem;
}

.composition {
  font-size: 2rem;
}

.notation {
  position: relative;
  display: inline-flex;
  align-items: stretch;
  padding: .15rem .9rem;
  color: inherit;
}

.notation::before,
.notation::after {
  position: absolute;
  top: 0;
  bottom: 0;
  width: .72rem;
  content: "";
  pointer-events: none;
}

.notation::before {
  left: 0;
  border-left: .32rem solid currentColor;
  border-radius: 65% 0 0 65% / 12% 0 0 12%;
}

.notation::after {
  right: 0;
  border-right: .32rem solid currentColor;
  border-radius: 0 65% 65% 0 / 0 12% 12% 0;
}

.notation .permutation {
  display: table;
  width: auto;
  margin: 0;
  overflow: visible;
  font-family: inherit;
  font-size: 1.25rem;
  border-collapse: collapse;
}

.notation .permutation td {
  min-width: 2.05rem;
  padding: .12rem .35rem;
  text-align: center;
  border: 0;
}

.answer-area {
  margin-top: 1.2rem;
}

.answer-input {
  width: 2.05rem !important;
  height: 2rem;
  padding: 0 !important;
  border: 0 !important;
  border-bottom: .12rem solid currentColor !important;
  border-radius: 0 !important;
  text-align: center;
  background: transparent !important;
  color: inherit !important;
  font: inherit;
  font-size: 1.2rem;
}

.answer-input:focus {
  outline: none;
  border-bottom-color: var(--focus) !important;
  background: var(--panel) !important;
}

.answer-input.incorrect,
.cycle-result .notation .permutation td.cycle-incorrect {
  outline: 3px solid var(--error);
  outline-offset: 1px;
  border-radius: 50% !important;
}

.answer-input.correct {
  border-bottom-color: var(--success) !important;
}

.check {
  min-height: 3.4rem;
  margin-top: 1.2rem;
  font-size: 3rem;
  line-height: 1;
}

.check.success,
.check small {
  color: var(--success);
}

.check.error {
  color: var(--error);
}

.cycle-given {
  margin: 1.25rem 0 .75rem;
}

.cycle-new-problem {
  margin-bottom: 1rem;
}

.cycle-label {
  display: block;
  margin-bottom: .25rem;
}

.cycle-answer-row {
  display: flex;
  align-items: center;
  gap: .5rem;
}

.equals {
  font-size: 1.5rem;
}

.cycle-answer {
  display: inline-block;
  width: min(30rem, 100%);
  padding: .25em .4em;
  color: var(--ink);
  background: #252a34;
  border: 1px solid var(--line);
  border-radius: 4px;
  font-size: 1.15rem;
}

.cycle-check {
  margin-top: 1.25rem;
}

.feedback-line {
  margin: .45rem 0;
  font-size: 1rem;
}

.feedback-line.success {
  color: var(--success);
}

.feedback-line.error {
  color: var(--error);
}

.feedback-symbol {
  display: inline-block;
  width: 1.4rem;
  font-size: 1.35rem;
  font-weight: bold;
}

.cycle-result {
  margin-top: 1rem;
}

[hidden] {
  display: none !important;
}

@media (max-width: 30rem) {
  main {
    margin: 1rem auto;
    padding: 1.25rem;
  }
}