* {
  box-sizing: border-box;
}

:root {
  font-size: clamp(16px, 1vw + 4px, 60px);

  --board-size-cols: 1;
  --board-size-rows: 1;
  --box-size: 7rem;
}

body {
  font-family: "Segoe UI", Tahoma, sans-serif;
  position: relative;
  margin: 0;
}

menu,
ul {
  padding: 0;
}

ul {
  list-style: none;
}

li {
  display: inline-block;
}

input {
  font-size: inherit;
  border: 0.1rem solid black;
  border-radius: 0.5rem;
}

input:focus {
  outline: 0.1rem solid green;
}

input:invalid {
  outline: 0.1rem solid red;
  background-color: rgb(255, 200, 200);
}

input[type="number"] {
  -webkit-appearance: textfield;
  -moz-appearance: textfield;
  appearance: textfield;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

button {
  width: 7rem;
  height: 3rem;
  border-radius: 1rem;
  border: 0.1rem solid black;
  cursor: pointer;
  transition: transform 0.2s;
  font-size: inherit;
}

button:hover {
  transform: scale(1.1);
}

button:active {
  transform: scale(0.9);
}

header,
main {
  padding: 0.5rem;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

header h1 {
  text-align: center;
}

header ul {
  text-align: right;
}

header menu button {
  margin: 0.5rem;
}

#btn-fullscreen {
  position: fixed;
  bottom: 1rem;
  left: 1rem;
  width: 3rem;
  height: 3rem;
  border-radius: 0.5rem;
  background-image: url("./images/fullscreen.png");
  background-repeat: no-repeat;
  background-position: center;
  background-size: 80%;
}

#btn-fullscreen.is-fullscreen {
  background-image: url("./images/smallscreen.png");
}

.settings.show {
  position: fixed;
  z-index: 999;
}

.settings.show {
  inset: 0;
  backdrop-filter: blur(0.2rem);
}

.settings form {
  display: grid;
  grid-template-columns: repeat(2, 12rem);
  grid-auto-rows: 1fr;
  align-items: center;
  position: absolute;
  top: 0;
  right: 50%;
  border-radius: 1rem;
  background-color: rgba(128, 128, 128, 0.8);
  transform: translate(50%, -100%);
  transition: transform 0.2s;
}

.settings.show form {
  transform: translate(50%, 20%);
}

.settings form label {
  display: block;
  padding: 0.5rem;
  text-align: center;
}

.settings form input {
  display: block;
  margin: 0.5rem auto;
  text-align: center;
  width: 5rem;
  height: 3rem;
}

.settings form span {
  display: block;
  height: 1rem;
}

.settings form input:invalid + span::before {
  content: attr(data-error-msg);
  color: red;
  font-size: 0.9rem;
  font-weight: bold;
  line-height: 1;
  vertical-align: top;
}

.settings form div:last-child {
  border-top: 0.2rem solid gray;
  padding: 0.5rem;
  grid-column: 1/-1;
  align-self: stretch;
  display: flex;
  align-items: center;
  justify-content: space-evenly;
  flex-wrap: wrap;
  gap: 0.5rem;
}

#btn-save-settings {
  background-color: green;
}

#btn-close-settings {
  background-color: rgb(210, 0, 0);
}

#info-container {
  text-align: center;
  font-weight: bold;
  margin-bottom: 1.2rem;
}

#info-container span {
  color: red;
}

#board-container {
  text-align: center;
}

.board {
  width: calc(var(--board-size-cols) * var(--box-size));
  height: calc(var(--board-size-rows) * var(--box-size));
  display: grid;
  grid-template-columns: repeat(var(--board-size-cols), 1fr);
  grid-template-rows: repeat(var(--board-size-rows), 1fr);
  grid-gap: calc(var(--box-size) / 20);
  margin: auto;
}

.block {
  background-color: rgb(170, 170, 170);
}

.selected {
  background-color: black;
}

.success {
  outline: 0.4rem solid green;
  outline-offset: 0.4rem;
}

.error {
  background-color: red;
}

@media screen and (max-width: 700px) {
  :root {
    --box-size: calc(75vw/var(--board-size-cols));
  }
}

@media screen and (max-width: 450px) {
  :root {
    --box-size: calc(85vw/var(--board-size-cols));
  }

  .settings form {
    grid-template-columns: repeat(2, 1fr);
    width: 90%;
    align-items: end;
  }

  .settings form span {
    height: 2rem;
  }
}