styles.css

:root {
    --darkviolet: rgba(148, 0, 211, 1);
    --mother-pink: rgba(232, 0, 118, 1);
    --father-blue: rgba(0, 146, 255, 1);
    --closest_organism_gold: rgba(255, 215, 0, 1);
    --custom-green: rgba(155, 245, 0, 1);
}

html {
    font-family: 'Cairo', 'Roboto', sans-serif;
    font-family: 'Roboto', sans-serif;
}

body {
    background: black;
}

button {
    font-family: 'Cairo';
}

#main-canvas, #background-canvas {
    border: 4px solid var(--darkviolet);
}

#main-canvas {
    background-color: transparent;
}

#background-canvas {
    position: absolute;
    top: 0;
    left: 0;
    z-index: -1;
}

/* images */
#logo, #press-start, #classic-example, #boundary-example {
    display: none;
}

/* containers */
.canvas-container, .btn-container, .settings-container {
    margin: 0 auto;
    width: 1000px;
}

.canvas-container {
    position: relative;
}

/* settings */
.settings-container {
    display: none;
    margin-bottom: .25rem;
    width: 1000px;
    height: 600px;
    border: 4px solid var(--darkviolet);
}

#apply-form {
    width: 900px;
    margin: 0 auto;
    margin-top: 25px;
}

.settings-grid {
    display: grid;
    grid-template-columns: 3fr 1fr;
    grid-template-rows: 1fr repeat(10, .7fr);
}

.settings-header {
    grid-column: 1 / 3;
    display: block;
    margin-bottom: 1.2rem;
    font-size: 30px;
    color: var(--darkviolet);
}

.apply-help-message {
    margin-left: 250px;
    color: darkviolet;
    font-size: 18px;
}

.organisms-setting-label,
.movement-setting-label,
.mutation-setting-label,
.growth-setting-label,
.resilience-setting-label,
.dialogue-setting-span {
    grid-column: 1 / 2;
    font-size: 24px;
    font-family: 'Cairo';
    color: var(--custom-green);
}

.setting-caption {
    display: block;
    color: var(--darkviolet);
    font-size: 16px;
}

.setting-caption-growth {
    font-size: 13px;
}

.dialogue-setting-span {
    display: block;
}

.dialogue-container {
    grid-column: 2 / 3;
    margin-left: 40px;
    margin-top: 1rem;
}

.setting-input {
    width: 50%;
    margin-left: auto;
    border: none;
    border-bottom: 2px solid var(--custom-green);
    text-align: right;
    font-family: 'Cairo';
    font-size: 22px;
    background-color: black;
    color: var(--custom-green);
    outline: none;
}

.growth-toggle-btn, .setting-submit {
    border-radius: 3px;
    background-color: black;
    color: var(--custom-green);
    transition: .25s;
}

.growth-div {
    position: relative;
    margin-left: auto;
}

.growth-toggle-btn {
    position: absolute;
    top: 20px;
    right: 0;
    width: 100px;
    border: 1px solid var(--custom-green);
    padding: .4rem 1rem;
    font-size: 16px;
}

.growth-toggle-btn:hover {
    border: 2px solid var(--custom-green);
    transition: .25s;
}

.setting-submit {
    display: none;
    grid-column: 2 / 3;
    margin: 0 auto;
    padding: .05rem 2rem;
    border: 2px solid var(--custom-green);
    font-size: 26px;
    transition: .25s;
}

.setting-submit:hover {
    background-color: var(--custom-green);
    color: black;
    transition: .25s;
}

/* custom checkbox */
.dialogue-setting-label {
    display: block;
    position: relative;
    padding-left: 35px;
    margin-bottom: 12px;
    cursor: pointer;
    font-size: 22px;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
  }
  
  /* hide browser default checkbox */
  .dialogue-setting-label input {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
  }
  
  /* create a custom checkbox */
  .checkmark {
    position: absolute;
    top: 0;
    right: 28px;
    height: 40px;
    width: 40px;
    border: 1px solid var(--custom-green);
    border-radius: 4px;
    background-color: black;
  }
  
  /* on mouse-over, add darkgray background color */
  .dialogue-setting-label:hover input ~ .checkmark {
    background-color: #222;
  }
  
  /* When the checkbox is checked, add black background */
  .dialogue-setting-label input:checked ~ .checkmark {
    background-color: black;
  }
  
  /* checkmark/indicator (hidden when not checked) */
  .checkmark:after {
    content: "";
    position: absolute;
    display: none;
  }
  
  /* show checkmark when checked */
  .dialogue-setting-label input:checked ~ .checkmark:after {
    display: block;
  }
  
  /* checkmark/indicator */
  .dialogue-setting-label .checkmark:after {
    left: 12px;
    top: 5px;
    width: 10px;
    height: 20px;
    border: solid var(--custom-green);
    border-width: 0 6px 6px 0;
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
  }
/* end custom checkbox */

/* buttons */
.btn-container {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
}

.start-btn, .sim-type-classic,
.sim-type-boundary, .run-btn,
.stop-btn, .sim-type-classic,
.sim-type-boundary, .next-btn,
.save-boundaries-btn {
    padding: .25rem 1rem;
    border: none;
    border-radius: 2px;
    font-size: 18px;
    transition: .25s;
}

.start-btn {
    grid-column: 2 / 3;
    margin: 0 auto;
    background-color: var(--custom-green);
}

.start-btn:hover {
    background-color: var(--darkviolet);
    color: var(--custom-green);
    transition: .5s;
}

.sim-type-classic, .sim-type-boundary {
    display: none;
    width: 50%;
    background-color: var(--darkviolet);
    color: var(--custom-green);
    transition: .25s;
}

.sim-type-classic {
    grid-column: 1 / 2;
    margin-right: .5rem;
    justify-self: end;
}   

.sim-type-boundary {
    grid-column: 3 / 4;
    margin-left: .5rem;
    justify-self: start;
}

.run-btn {
    display: none;
    grid-column: 2 / 3;
    margin: 0 auto;
    background-color: var(--custom-green);
}

.run-btn:hover {
    background-color: var(--darkviolet);
    color: var(--custom-green);
    transition: .5s;
}

.stop-btn {
    display: none;
    grid-column: 1 / 2;
    grid-row: 1 / 2;
    margin-right: auto;
    background-color: var(--darkviolet);
}

.stop-btn:hover {
    background-color: var(--mother-pink);
    transition: .5s;
}

.next-btn {
    display: none;
    grid-column: 2 / 3;
    background-color: rgba(148, 0, 211, 1);
    color: rgba(155, 245, 0, 1);
}

.next-btn:hover {
    background-color: rgba(155, 245, 0, 1);
    color: black;
}

.save-boundaries-btn {
    display: none;
    grid-column: 2 / 3;
    border: none;
    background-color: var(--custom-green);
    font-size: 20px;
    transition: .25s;
}

.save-boundaries-btn:hover {
    background-color: var(--darkviolet);
    color: var(--custom-green);
    transition: .25s;
}

.skip-btn {
    display: none;
    grid-column: 2 / 3;
    border: none;
    border-radius: 2px;
    background-color: var(--darkviolet);
    transition: .25s;
    font-size: 18px;
}

.skip-btn:hover {
    color: var(--custom-green);
    transition: .25s;
}