:root {
  --color-bg: #fff;
  --color-primary: #08031e;
  --color-primary-muted: #888888;
  --color-secondary: #00fff8;
  --color-accent: #300888;
  --color-action: #ffc163;
  --color-action-dark: #ff8856;
  --color-error: #c30;
  --color-success: #3c0;

  --logo-size: 2.5rem;
  --logo-spacing: 1rem;

  --form-step-gap: 2.5rem;
  --form-field-spacing: 0.5rem;
  --form-field-border-radius: 0.25rem;
  --form-field-border-width: 0.125rem;

  --font-line-height: 1.4;

  @media (width > 40rem) {
    --logo-size: 4rem;
    --form-step-gap: 3.5rem;
  }
}

body {
  background-color: var(--color-bg);
  color: var(--color-primary);
  font-family: system-ui;
  line-height: var(--font-line-height);
  margin: 0;
}

h1 {
  font-size: 1.25rem;

  @media (width > 40rem) {
    font-size: 2rem;
  }
}

h2 {
  font-size: 1.125rem;

  @media (width > 40rem) {
    font-size: 1.5rem;
  }
}

a {
  color: var(--color-accent);
}

.container {
  --container-spacing: 1rem;

  padding-inline: var(--container-spacing);
  max-width: 40rem;
  margin-inline: auto;
  box-sizing: border-box;
}

header {
  background-color: var(--color-primary);
  color: var(--color-secondary);
  padding-block: 1rem;

  .container {
    display: flex;
    align-items: center;
    gap: var(--logo-spacing);
  }

  img {
    display: block;
    width: var(--logo-size);
  }
}

main {
  padding-block: 1rem;

  @media (width > 40rem) {
    .container {
      padding-inline-start: calc(
        var(--container-spacing) + var(--logo-size) + var(--logo-spacing)
      );
    }
  }
}

input,
textarea,
select {
  font: inherit;
  background-color: var(--color-bg);
  color: inherit;
  accent-color: var(--color-primary);

  &:not([type="checkbox"], [type="radio"], [type="file"]) {
    padding: var(--form-field-spacing);
    border: var(--form-field-border-width) solid currentColor;
    border-radius: var(--form-field-border-radius);
  }

  &:is(select) {
    height: 42px;
  }

  &[readonly="true"],
  &[aria-readonly="true"] {
    opacity: 0.5;
    cursor: not-allowed;
  }
  &[aria-readonly="true"] {
    pointer-events: none;
  }
}

textarea {
  min-height: calc(4em * var(--font-line-height));
  field-sizing: content;
}

button {
  appearance: none;
  border: 0;
  background: linear-gradient(
    90deg,
    var(--color-action) 0%,
    var(--color-action-dark) 100%
  );
  color: currentColor;
  border-radius: var(--form-field-border-radius);
  font: inherit;
  padding: var(--form-field-spacing) calc(var(--form-field-spacing) * 2);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

fieldset {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 0;
  border: 0;
  margin: 0;
}

/**
 * Notification
 */
.notification {
  --notification-color: var(--color-secondary);

  border: 1px solid var(--notification-color);
  border-radius: var(--form-field-border-radius);
  padding: 1rem;
  background-color: color-mix(in srgb, var(--notification-color) 20%, white);

  :first-child {
    margin-block-start: 0;
  }
  :last-child {
    margin-block-end: 0;
  }

  pre {
    white-space: normal;
  }
}
.notification--warning {
  --notification-color: var(--color-action);
}
.notification--error {
  --notification-color: var(--color-error);
}
.notification--success {
  --notification-color: var(--color-success);
}
.notification--intro {
  margin-block-end: 2rem;
}

/**
 * Form elements
 */
.form {
  display: flex;
  flex-direction: column;
  gap: var(--form-step-gap);

  button {
    align-self: flex-start;
  }
}

.form__group {
  border-block-start: 0.125rem solid;
  padding-block-start: var(--form-step-gap);

  fieldset {
    margin-top: 1rem;
  }

  summary * {
    display: inline;
  }
}

.form__row {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;

  &:not(:has(input[type="checkbox"])) {
    label {
      font-weight: bold;
    }
  }

  &:has(input[type="checkbox"]) {
    flex-direction: row;
    flex-wrap: wrap;

    label {
      order: 1;
    }

    .form__hint {
      order: 2;
      flex-basis: 100%;
    }
  }

  &[hidden] {
    display: none;
  }
}

.form__hint {
  margin: 0;
  color: var(--color-primary-muted);
  font-style: italic;
}

.form__attachments {
  border: var(--form-field-border-width) solid currentColor;
  border-radius: var(--form-field-border-radius);
  display: flex;
  align-items: center;
  padding-inline: var(--form-field-spacing);
  gap: 8px;

  img {
    display: block;
    width: 25px;
    height: 25px;
    object-fit: contain;
    border-radius: var(--form-field-border-radius);
    border: 1px solid color-mix(in srgb, var(--color-primary) 25%, transparent);
  }

  input {
    padding-block: var(--form-field-spacing);
    flex-grow: 1;
    width: 100%;
  }
}

/**
 * Minimal loading spinner
 * https://codepen.io/EastingAndNorthing/pen/aNWrZz
 */
.spinner {
  --size: 0.75em;

  display: block;
  width: var(--size);
  height: var(--size);
  border: 0.125em solid transparent;
  border-color: rgba(0, 0, 0, 0.25);
  border-top-color: rgba(0, 0, 0, 1);
  border-radius: 50%;
  animation: spinner 1s linear infinite;
}

@keyframes spinner {
  100% {
    transform: rotate(360deg);
  }
}

/**
 * Hide content visually
 * https://www.scottohara.me/blog/2017/04/14/inclusively-hidden.html
 */
.visually-hidden:not(:focus):not(:active) {
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  height: 1px;
  overflow: hidden;
  position: absolute;
  white-space: nowrap;
  width: 1px;
}