html {
  box-sizing: border-box;
}

:root {
  --primary-color: #2034c5;
  --primary-color-hover: #0f23ba;
  --secondary-color: #e9e6f0;
  --secondary-color-hover: #ddd9eb;
  --accent-color: #15b48a;
  --bg-color: linear-gradient(to bottom right, #0c197d, #134a3c);
  --text-color: #333;
  --text-color-hover: #222;
  --shadow: 1px 1px 5px 1px rgba(0, 0, 0, 0.2);
  --font-family: 'Noto Sans', sans-serif;
  --calculator-font-family: 'Noto Sans Math', sans-serif;
  color-scheme: light;
}

:root.dark {
  --primary-color: #15b48a;
  --primary-color-hover: #19ca9b;
  --secondary-color: #131416;
  --secondary-color-hover: #25272b;
  --accent-color: #17a27d;
  --text-color: #eee;
  --text-color-hover: #fff;
  --shadow: 1px 1px 5px 1px rgba(0, 0, 0, 0.5);
  color-scheme: dark;
}

*,
*::before,
*::after {
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

* {
  -webkit-tap-highlight-color: transparent;
}

/* General styles */
body {
  max-width: 100%;
  min-height: 100vh;
  background-image: var(--bg-color);
  font-family: var(--font-family);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow-y: scroll;
  overflow-x: hidden;
}

.hidden {
  display: none;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  border: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

/* Custom tooltip styles */
.tooltip {
  position: absolute;
  top: 110%;
  left: 0;

  background-color: rgba(0, 0, 0, 0.8);
  color: #fff;
  outline: 2px solid #fff;
  box-shadow: 1px 1px 3px rgba(0, 0, 0, 0.2);

  padding: 0.3rem 0.5rem;
  font-family: var(--font-family);
  font-size: 0.92rem;
  font-weight: 400;
  text-align: center;
  white-space: nowrap;

  visibility: hidden;
  opacity: 0;
  pointer-events: none;
  transition:
    visibility 0s linear 600ms,
    opacity 0.3s ease;
}

.tooltip.ln {
  left: -90%;
}

.tooltip.inverse {
  left: -20%;
}

.tooltip.angle {
  left: -130%;
}

.tooltip.flipped {
  left: auto;
  right: 0;
}

/* Navbar styles */
nav {
  width: 100%;
  height: 50px;
  padding: 3rem 0;
  display: flex;
  justify-content: flex-end;
  align-items: center;
}

/* Modal button styles */
#keyboard-shortcuts {
  margin: 0.5rem;
}

#show-dialog-btn {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--secondary-color);
  background-color: transparent;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  padding: 0.5rem 0.8rem;
  position: relative;
}

.dark #show-dialog-btn {
  color: var(--text-color);
}

@media (hover: hover) {
  #show-dialog-btn:hover {
    background-color: var(--secondary-color);
    color: var(--primary-color);
  }

  .dark #show-dialog-btn:hover {
    color: var(--text-color-hover);
  }

  #show-dialog-btn:hover .tooltip {
    visibility: visible;
    opacity: 1;
    transition-delay: 600ms;
  }
}

#show-dialog-btn:focus-visible {
  background-color: var(--secondary-color);
  color: var(--primary-color);
}

#show-dialog-btn:active {
  background-color: var(--secondary-color-hover);
}

#show-dialog-btn:active,
#show-dialog-btn:focus-visible {
  outline: 2px solid var(--secondary-color);
  outline-offset: 2px;
}

.dark #show-dialog-btn:focus-visible {
  color: var(--text-color-hover);
}

.dark #show-dialog-btn:active,
.dark #show-dialog-btn:focus-visible {
  outline: 2px solid var(--text-color);
  outline-offset: 2px;
}

/* Modal styles */
#keyboard-shortcuts-dialog {
  width: 100%;
  max-width: 600px;
  margin: auto;
  padding: 0.5rem;
  border-radius: 0.5rem;
  scrollbar-width: thin;
  background-image: var(--bg-color);
  color: var(--secondary-color);
}

.dark #keyboard-shortcuts-dialog {
  color: var(--text-color);
}

::backdrop {
  background-image: var(--bg-color);
  opacity: 0.8;
}

#shortcuts-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

#shortcuts-header #modal-title {
  font-size: 1.5rem;
  font-weight: 600;
  padding: 1rem 0.5rem;
}

#close-dialog-btn {
  cursor: pointer;
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 0.5rem;
  background-color: var(--secondary-color);
  color: var(--text-color);
  padding: 1rem 1.5rem;
}

#close-dialog-btn:hover,
#close-dialog-btn:active,
#close-dialog-btn:focus-visible {
  background-color: var(--secondary-color-hover);
  color: var(--text-color-hover);
}

#close-dialog-btn:active,
#close-dialog-btn:focus-visible {
  outline: 2px solid var(--secondary-color);
  outline-offset: 2px;
}

.dark #close-dialog-btn:active,
.dark #close-dialog-btn:focus-visible {
  outline: 2px solid var(--text-color);
}

#note {
  margin: 0.7rem 0.5rem;
}

#note strong {
  display: inline-block;
  margin: 0.5rem 0;
}

fieldset {
  width: 100%;
  padding: 0.5rem;
  margin: 1rem 0;
  border-radius: 0.5rem;
}

legend {
  font-size: 1.2rem;
  font-weight: 600;
  padding: 0 0.5rem;
}

ul li {
  list-style-type: none;
  margin: 0.7rem 0;
  font-size: 1rem;
}

ul li span {
  display: inline-block;
  padding: 0.3rem 0.6rem;
  margin: 0.2rem 0;
  background-color: var(--secondary-color);
  color: var(--text-color);
}

/* GitHub link styles */
#github-link-container {
  display: flex;
  justify-content: center;
  align-items: center;
}

#github-link-container a {
  padding: 0.5rem 0.8rem;
  position: relative;
}

@media (hover: hover) {
  #github-link-container a:hover {
    background-color: rgba(255, 255, 255, 0.06);
    border-radius: 0.5rem;
  }

  #github-link-container a:hover .tooltip {
    visibility: visible;
    opacity: 1;
    transition-delay: 600ms;
  }
}

#github-link-container a:focus-visible {
  background-color: rgba(255, 255, 255, 0.06);
  border-radius: 0.5rem;
}

#github-link-container a:active {
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: 0.5rem;
}

#github-link-container a:active,
#github-link-container a:focus-visible {
  outline: 2px solid var(--secondary-color);
  outline-offset: 2px;
}

.dark #github-link-container a:active,
.dark #github-link-container a:focus-visible {
  outline: 2px solid var(--text-color-hover);
}

.github-logo {
  width: 40px;
  height: 40px;
}

/* Light / Dark mode toggle styles */
#theme-switch {
  margin: 0.5rem;
}

label {
  width: 100px;
  height: 50px;
  position: relative;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--secondary-color);
  border-radius: 50px;
  cursor: pointer;
}

label::after {
  content: '';
  width: 42px;
  height: 42px;
  position: absolute;
  top: 4px;
  left: 4px;
  background-color: var(--primary-color);
  border-radius: 42px;
}

input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
  pointer-events: none;
  outline: none;
}

input:focus-visible + label::after {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

.dark input:focus-visible + label::after {
  outline: 2px solid var(--text-color);
}

input:checked + label {
  background-color: var(--secondary-color);
}

input:checked + label::after {
  top: 4px;
  right: 4px;
  transform: translateX(50px);
  background-color: var(--primary-color);
}

label,
label::after {
  transition: transform 0.4s ease;
}

label:hover::after,
input:checked + label:hover::after {
  background-color: var(--primary-color-hover);
}

label i {
  font-size: 25px;
  position: absolute;
  z-index: 99;
  transition: background-color 0.4s ease;
}

@media (hover: hover) {
  label i:hover .tooltip {
    visibility: visible;
    opacity: 1;
    transition-delay: 600ms;
    font-style: normal;
  }
}

label i:not(:hover) .tooltip {
  transition-delay: 0s;
}

label .bi.bi-brightness-high-fill {
  top: 8px;
  left: 12px;
  color: var(--secondary-color);
}

label .bi.bi-brightness-high-fill:hover {
  color: #fff;
}

label .bi.bi-brightness-high-fill:hover .tooltip {
  top: 140%;
  left: -20%;
}

label .bi.bi-moon-stars-fill {
  top: 8px;
  right: 12px;
  color: var(--text-color);
}

label .bi.bi-moon-stars-fill:hover {
  color: var(--text-color-hover);
}

label .bi.bi-moon-stars-fill:hover .tooltip {
  top: 140%;
}

input:checked + label .bi.bi-brightness-high-fill {
  color: #7e7e7e;
}

input:checked + label .bi.bi-brightness-high-fill:hover {
  color: var(--text-color);
}

input:checked + label .bi.bi-moon-stars-fill {
  color: var(--secondary-color);
}

input:checked + label .bi.bi-moon-stars-fill:hover {
  color: var(--secondary-color-hover);
}

/* Calculator container and display styles */
#calculator {
  width: 95%;
  min-width: 250px;
  max-width: 400px;
  background-color: var(--secondary-color);
  margin: 2rem auto 2rem;
  border-radius: 1rem;
  box-shadow: var(--shadow);
}

.display-container {
  width: 100%;
  padding: 1rem;
  border-top-left-radius: 1rem;
  border-top-right-radius: 1rem;
  box-shadow: var(--shadow);
}

.display {
  width: 100%;
  background-color: var(--secondary-color);
  color: var(--text-color);
  border: none;
}

#angle-display {
  padding-bottom: 0.5rem;
}

#expression-display,
#result-display {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 0.2rem;
  overflow: auto;
}

#expression-display {
  height: 80px;
  font-size: clamp(1.5rem, 4vw, 2rem);
  line-height: 1.2;
}

#result-display {
  height: 60px;
  font-size: clamp(1.3rem, 4vw, 1.8rem);
}

/* Calculator keypad styles */
#keypad-container {
  width: 100%;
  display: flex;
  flex-direction: column;
}

.keypad {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  padding: 0.5rem;
}

.calculator-btn {
  font-family: var(--calculator-font-family);
  font-size: 1.5rem;
  max-width: calc(400px / 4);
  min-height: 40px;
  border-radius: 0.5rem;
  border: none;
  margin: 0.3rem;
  background-color: var(--secondary-color);
  color: var(--text-color);
  box-shadow: var(--shadow);
  cursor: pointer;
  position: relative;
  transition: transform 0.1s;
}

.calculator-btn:hover {
  transition: background-color 0.2s;
}

.calculator-btn:active {
  transition:
    transform 0.1s,
    background-color 0.2s;
  transform: scale(0.95);
}

@media (hover: hover) {
  .calculator-btn:hover .tooltip {
    visibility: visible;
    opacity: 1;
    transition-delay: 600ms;
    z-index: 9999;
  }

  .calculator-btn:not(#equals):hover {
    background-color: var(--secondary-color-hover);
  }

  .calculator-btn:not(.operator):hover {
    color: var(--text-color-hover);
  }

  .operator:hover,
  #backspace:hover,
  #clear:hover {
    color: var(--primary-color-hover);
  }

  #equals:hover {
    background-color: var(--primary-color-hover);
    color: #fff;
  }
}

.calculator-btn:not(:hover) .tooltip {
  transition-delay: 0s;
}

.calculator-btn:not(#equals):active,
.calculator-btn:not(#equals):focus-visible {
  background-color: var(--secondary-color-hover);
}

.calculator-btn:not(#equals):focus-visible {
  outline: 2px solid var(--primary-color);
}

.calculator-btn:not(.operator):active,
.calculator-btn:not(.operator):focus-visible {
  color: var(--text-color-hover);
}

.operator,
#backspace .bi.bi-backspace-fill,
#clear {
  color: var(--primary-color);
  font-weight: 700;
}

.operator:active,
.operator:focus-visible,
#backspace:active,
#backspace:focus-visible,
#clear:active,
#clear:focus-visible {
  color: var(--primary-color-hover);
}

.scientific,
.parenthesis,
#mode-toggle {
  font-size: 1.2rem;
}

#equals {
  grid-column: 4 / 5;
  grid-row: 4 / 6;
  background-color: var(--primary-color);
  color: var(--secondary-color);
  font-weight: 700;
}

#equals:active {
  background-color: var(--primary-color-hover);
  color: #fff;
}

#equals:focus-visible {
  background-color: var(--secondary-color-hover);
  color: var(--primary-color-hover);
  outline: 2px solid var(--primary-color-hover);
}

.button-active {
  animation: flash 0.2s;
}

.equals-active {
  animation: flash-equals 0.2s;
}

@keyframes flash {
  0% {
    background-color: var(--accent-color);
  }
  100% {
    background-color: var(--secondary-color);
  }
}

@keyframes flash-equals {
  0% {
    background-color: var(--secondary-color);
    color: var(--primary-color);
  }
  100% {
    background-color: var(--primary-color);
    color: var(--secondary-color);
  }
}

/* Footer styles */
footer {
  width: 100%;
  padding: 2rem 0;
  text-align: center;
  align-self: flex-end;
}

footer small {
  font-size: 1rem;
  color: var(--secondary-color);
}

.dark footer small {
  color: var(--text-color);
}

/* Styles for users who prefer reduced motion*/
@media (prefers-reduced-motion: reduce) {
  * {
    animation: none;
    transition: none;
  }
}

/* Responsive breakpoints */
@media screen and (min-width: 360px) {
  .tooltip.ln {
    left: -50%;
  }

  .tooltip.inverse {
    left: 0;
  }

  .tooltip.angle {
    left: -90%;
  }
}

@media screen and (min-width: 407px) {
  .tooltip.ln {
    left: 0;
  }

  .tooltip.angle {
    left: -30%;
  }

  #show-dialog-btn {
    padding: 1.2rem 0.8rem;
  }
}

@media screen and (min-width: 430px) {
  .tooltip.angle {
    left: 0;
  }
}

@media screen and (min-width: 460px) {
  #show-dialog-btn {
    font-size: 1.2rem;
  }

  #github-link-container {
    margin: 1rem;
  }

  #calculator {
    width: 90%;
  }
}

@media screen and (min-width: 560px) {
  #note,
  ul li {
    padding-left: 0.5rem;
  }
}

@media screen and (min-width: 768px) {
  .tooltip.angle {
    left: -30%;
  }

  #keyboard-shortcuts-dialog {
    scrollbar-width: auto;
  }

  #calculator {
    width: 100%;
    max-width: 750px;
  }

  #keypad-container {
    flex-direction: row;
  }

  .keypad {
    width: 50%;
  }

  .calculator-btn {
    font-size: 1.8rem;
  }

  .scientific,
  .parenthesis {
    font-size: 1.3rem;
  }

  #clear {
    font-size: 1.6rem;
  }
}

@media screen and (min-width: 840px) {
  .tooltip.angle {
    left: 0;
  }
}