@font-face {
  font-family: "Space Mono";
  font-style: normal;
  src: url("assets/fonts/SpaceMono-Bold.ttf") format("truetype");
  font-weight: 700;
}

:root {
  --green-400: hsl(172, 67%, 45%);
  --primary: var(--green-400);

  --green-900: hsl(183, 100%, 15%);
  --grey-500: hsl(186, 14%, 43%);
  --grey-400: hsl(184, 14%, 56%);
  --grey-200: hsl(185, 41%, 84%);
  --grey-50: hsl(189, 47%, 97%);

  --white: hsl(0, 100%, 100%);
  --error: hsl(8, 64%, 62%);

  /* Light mode colors (default) */
  --bg-primary: var(--grey-200);
  --bg-secondary: var(--white);
  --text-primary: var(--green-900);
  --text-secondary: var(--grey-500);
  --input-bg: var(--grey-50);
  --input-border: var(--grey-50);
}

[data-theme="dark"] {
  --green-400: hsl(172, 67%, 45%);
  --primary: var(--green-400);

  --green-900: hsl(183, 100%, 15%);
  --grey-500: hsl(186, 14%, 43%);
  --grey-400: hsl(184, 14%, 56%);
  --grey-200: hsl(185, 41%, 84%);
  --grey-50: hsl(189, 47%, 97%);

  --white: hsl(0, 100%, 100%);
  --error: hsl(8, 64%, 62%);

  /* Dark mode colors */
  --bg-primary: hsl(183, 100%, 8%);
  --bg-secondary: hsl(183, 50%, 12%);
  --text-primary: var(--white);
  --text-secondary: var(--grey-200);
  --input-bg: hsl(183, 50%, 15%);
  --input-border: hsl(183, 30%, 20%);
}

* {
  font-family: "Space Mono", monospace;
}

.sr-only {
  position: absolute;
  width: 0.01em;
  height: 0.01em;
  padding: 0;
  margin: -0.01em;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

body {
  font-family: "Space Mono", monospace;
  font-weight: 700;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  margin: 0;
  padding: 1rem;
  display: grid;
  place-items: center;
  min-block-size: 100vh;
  box-sizing: border-box;
  transition: background-color 0.3s ease, color 0.3s ease;
}

@media screen and (max-width: 768px) {
  body {
    padding: 0.5rem;
  }
}

header {
  font-variant: small-caps;
  letter-spacing: 0.5em;
  color: var(--text-secondary);
  line-height: 1;
  margin-bottom: 2rem;
}

@media screen and (max-width: 480px) {
  header {
    font-size: 1.2rem;
    margin-bottom: 1rem;
  }
}

main {
  display: contents;
}

form {
  display: flex;
  flex-direction: column;
  background-color: var(--bg-secondary);
  border-radius: 1em;
  inline-size: 100%;
  max-inline-size: 57.5rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  transition: background-color 0.3s ease;
}

@media screen and (min-width: 50rem) {
  form {
    flex-direction: row;
  }
}

@media screen and (max-width: 480px) {
  form {
    border-radius: 0.5em;
    min-height: auto;
  }
}

.input {
  padding: 1em;
  border: none;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 2em;
  flex-grow: 1;
}

@media screen and (max-width: 480px) {
  .input {
    padding: 0.75em;
    gap: 1.5em;
  }
}

/* form styles */
.form-group {
  display: grid;
  gap: 1em;
  position: relative;
}

.form-group:has([aria-describedby]) {
  grid-template-columns: 1fr 1fr;
}

.form-group:has([aria-describedby]) input {
  grid-column: 1/-1;
}

.form-group:has([aria-describedby]) input:not(:user-invalid) + .input-error {
  display: none;
}

.form-group.bill-group {
  grid-template-columns: 1fr 1fr;
}

.form-group.bill-group input {
  grid-column: 1/-1;
}

.form-group.bill-group .input-error {
  position: absolute;
  top: 0;
  right: 0;
  z-index: 10;
}

.form-group .input-error {
  position: absolute;
  top: 0;
  right: 0;
  z-index: 10;
  color: var(--error);
  font-size: 0.875rem;
  font-weight: 700;
  padding: 2px 4px;
  border-radius: 4px;
}

fieldset[role="radiogroup"] legend {
  grid-column: 1/-1;
  margin-block-end: 1em;
}

.radio-group {
  --grid-max-col-count: 3;
  --grid-min-col-size: 7rem;
  --grid-gap: 1rem;
  --total-gap: calc(var(--grid-gap) * (var(--grid-max-col-count) - 1));
  --grid-col-size-calc: calc(
    (100% - var(--total-gap)) / var(--grid-max-col-count)
  );
  --grid-col-min-size-calc: min(
    100%,
    max(var(--grid-min-col-size), var(--grid-col-size-calc))
  );

  grid-template-columns: repeat(
    auto-fit,
    minmax(var(--grid-col-min-size-calc), 1fr)
  );
  border: 0;
  padding: 0;
  margin: 0;
}

@media screen and (max-width: 480px) {
  .radio-group {
    --grid-max-col-count: 2;
    --grid-min-col-size: 5rem;
    --grid-gap: 0.75rem;
  }
}

.radio-group .custom {
  position: relative;
}

.radio-group .custom .input-error {
  position: absolute;
  top: -1.5em;
  right: 0;
  z-index: 10;
  color: var(--error);
  font-size: 0.875rem;
  font-weight: 700;
  padding: 2px 4px;
  border-radius: 4px;
  white-space: nowrap;
}

.radio-group input:focus + label {
  background-color: var(--grey-200);
  color: var(--green-900);
}

.radio-group label {
  background-color: var(--green-900);
  color: var(--white);
  font-size: 1.5rem;
  padding: 0.5em;
  text-align: center;
  border-radius: 0.25em;
  cursor: pointer;
  transition: all 0.3s ease;
}

@media screen and (max-width: 480px) {
  .radio-group label {
    font-size: 1.25rem;
    padding: 0.75em 0.5em;
  }
}

.radio-group label:hover {
  background-color: var(--grey-200);
  color: var(--green-900);
}

.radio-group label.custom-tip {
  padding: 0;
}

.radio-group :checked + label {
  background-color: var(--primary);
  color: var(--green-900);
}

.radio-group input {
  text-align: center;
}

.radio-group input[type="text"] {
  inline-size: 100%;
  block-size: 100%;
  font-size: 1.5rem;
  padding: 0.5em;
  border-radius: 0.25em;
  border: none;
  background-color: var(--input-bg);
  color: var(--text-primary);
  text-align: center;
  min-height: 3em;
  box-sizing: border-box;
  transition: border-color 0.3s ease, background-color 0.3s ease;
}

@media screen and (max-width: 480px) {
  .radio-group input[type="text"] {
    font-size: 1.25rem;
    min-height: 2.5em;
  }
}

.radio-group input[type="text"]:hover,
.radio-group input[type="text"]:focus-visible {
  border: 0.125rem solid var(--primary);
  outline: none;
  cursor: pointer;
}

.radio-group input[type="text"]::placeholder {
  color: var(--grey-400);
}

button {
  background-color: var(--primary);
  color: var(--green-900);
  border-radius: 0.25em;
  border: none;
  padding: 0.5em;
  font-size: 1.5rem;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.3s ease, transform 0.2s ease;
}

@media screen and (max-width: 480px) {
  button {
    font-size: 1.25rem;
    padding: 0.75em;
  }
}

button:hover {
  transform: translateY(-1px);
}

button[type="reset"] {
  font-variant: small-caps;
  margin-block-start: auto;
}

input {
  background-color: var(--input-bg);
  background-image: var(--icon-url);
  background-size: 0.5em;
  background-repeat: no-repeat;
  background-position: left 0.75em center;
  border: 0.125rem solid var(--input-border);
  font-size: 1.5rem;
  padding: 0.25em;
  color: var(--text-primary);
  text-align: end;
  border-radius: 0.25em;
  transition: border-color 0.3s ease, background-color 0.3s ease;
}

@media screen and (max-width: 480px) {
  input {
    font-size: 1.25rem;
    padding: 0.5em;
  }
}

input:hover,
input:focus-visible {
  border-color: var(--primary);
  outline: none;
  cursor: pointer;
}

input::placeholder {
  color: var(--grey-400);
}

input:user-invalid {
  border-color: var(--error);
}

input.error {
  border-color: var(--error) !important;
}

.radio-group input[type="text"].error {
  border: 0.125rem solid var(--error) !important;
}

input#bill {
  --icon-url: url("assets/images/icon-dollar.svg");
}

input#people {
  --icon-url: url("assets/images/icon-person.svg");
}

.output {
  display: flex;
  flex-direction: column;
  padding: 1.5em;
  border: none;
  border-radius: 1em;
  background-color: var(--green-900);
  margin: 1em;
  color: var(--white);
  gap: 1em;
  flex-grow: 1;
}

@media screen and (max-width: 480px) {
  .output {
    padding: 1em;
    margin: 0.5em;
    gap: 0.75em;
  }
}

.output .form-group {
  grid-template-columns: 1fr 10ch;
  font-size: 1.5rem;
}

@media screen and (max-width: 480px) {
  .output .form-group {
    font-size: 1.25rem;
    grid-template-columns: 1fr 8ch;
  }
}

.output label {
  font-size: 0.75em;
  line-height: 1.15;
  align-self: center;
}

.output label span {
  font-size: 0.75em;
  color: var(--grey-400);
}

.output output {
  font-size: 2rem;
  color: var(--primary);
  justify-self: end;
}

@media screen and (max-width: 480px) {
  .output output {
    font-size: 1.5rem;
  }
}

.wrapper {
  display: grid;
  gap: 1em;
  margin-block: 1em;
}

/* Theme Toggle Button */
.theme-toggle {
  position: fixed;
  top: 1rem;
  right: 1rem;
  background-color: var(--bg-secondary);
  border: 2px solid var(--primary);
  border-radius: 50%;
  width: 3rem;
  height: 3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.2rem;
  transition: all 0.3s ease;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.theme-toggle:hover {
  background-color: var(--primary);
  color: var(--green-900);
  transform: scale(1.1);
}

@media screen and (max-width: 480px) {
  .theme-toggle {
    width: 2.5rem;
    height: 2.5rem;
    font-size: 1rem;
    top: 0.5rem;
    right: 0.5rem;
  }
}