:root {
  /* Colors */
  --color-primary-green: #2e7d32;
  --color-white: white;
  --color-black: #000000;
  --color-red: #b22222;
  --color-light-gray: #f0f0f0;
  --color-dark-gray: #ccc;
  --color-medium-gray: #666;
  --color-darker-gray: #333;
  --color-light-blue: #eaf2fa;
  --color-blue: #337ab7;
  --color-primary-blue: #007bff;
  --color-primary-blue-hover: #0056b3;
  --color-shadow-light: rgba(0, 0, 0, 0.1);
  --color-shadow-medium: rgba(0, 0, 0, 0.2);
  --color-error-background: #f8d7da;
  --color-error-text: #721c24;
  --color-error-border: #f5c6cb;
  --color-info-background: #d4edda;
  --color-info-text: #155724;
  --color-info-border: #c3e6cb;
  --color-disabled-background: #cccccc;
  --color-disabled-text: #666666;
  --color-disabled-border: #cccccc;
  --color-play-button: #4caf50;
  --color-pass-button: #f44336;
  --color-new-game-button: #008cba;

  /* Spacing */
  --spacing-xxs: 3px;
  --spacing-xs: 5px;
  --spacing-s: 10px;
  --spacing-m: 15px;
  --spacing-l: 20px;
  --spacing-xl: 25px;
  --spacing-xxl: 80px;

  /* Font Sizes */
  --font-size-xxs: 0.8em;
  --font-size-xs: 0.9em;
  --font-size-s: 1em;
  --font-size-m: 1.2em;
  --font-size-l: 1.5em;
  --font-size-xl: 2.5em;

  /* Other */
  --border-radius-s: 5px;
  --border-radius-m: 8px;
  --box-shadow-s: 2px 2px 5px var(--color-shadow-light);
  --box-shadow-m: 4px 4px 10px var(--color-shadow-medium);
  --transition-ease: all 0.2s ease-in-out;
  --transition-background: background-color 0.2s ease-in-out;
}

:root {
  --color-start-button: var(--color-new-game-button);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

body {
  font-family: sans-serif;
  background-color: var(--color-light-gray);
  padding-bottom: var(--spacing-xxl);
}

#game-container {
  display: flex;
  flex-direction: column;
  height: 100%;
}

header {
  background-color: var(--color-primary-green);
  padding: 0.5em 0;
  text-align: center;
  color: var(--color-white);
  flex-shrink: 0;
}

header a,
header a:visited {
  color: var(--color-light-gray);
  text-decoration: none;
}

header a:hover {
  text-decoration: underline;
}

.logo {
  width: 100px;
  margin: 0 auto;
  display: block;
}

h1 {
  font-size: var(--font-size-l);
  text-shadow: 2px 2px 4px var(--color-shadow-light);
  margin: 0;
}

h2 {
  font-size: var(--font-size-s);
  margin: 0;
  margin-bottom: var(--spacing-xs);
}

#game-board {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--spacing-xs) 0;
  flex-grow: 1;
}

#play-area {
  margin-bottom: var(--spacing-s);
  padding: var(--spacing-s);
  border: 1px solid var(--color-dark-gray);
  border-radius: var(--border-radius-m);
  width: 90%;
  max-width: 800px;
  background-color: var(--color-white);
  box-shadow: var(--box-shadow-s);
}

#players-hands {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 95%;
  max-width: 800px;
  gap: var(--spacing-s);
}

.player-hand {
  flex: 1;
  position: relative;
  border: 1px solid var(--color-dark-gray);
  border-radius: var(--border-radius-m);
  background-color: #f9f9f9;
  box-shadow: var(--box-shadow-s);
  width: 95%;
  max-width: 800px;
  padding: var(--spacing-xs);
  padding-bottom: var(--spacing-l);
  height: 200px;
}

.player-hand.ai .card {
  filter: blur(5px);
}

.player-hand.current {
  border: 2px solid var(--color-blue);
  background-color: var(--color-light-blue);
}

.games-won {
  font-size: var(--font-size-s);
  color: var(--color-darker-gray);
  font-weight: bold;
  margin-bottom: 0;
  padding: 0 var(--spacing-m);
}

.rounds-won {
  font-size: var(--font-size-xs);
  color: var(--color-medium-gray);
  margin: 0;
  padding: 0 var(--spacing-m);
}

.combination-type {
  font-size: var(--font-size-xxs);
  color: var(--color-medium-gray);
  margin-left: var(--spacing-xs);
}

.cards-container {
  display: flex;
  flex-wrap: nowrap;
  justify-content: center;
  overflow-x: hidden;
  padding: var(--spacing-m) var(--spacing-m);
}

#play-area .cards-container {
  justify-content: flex-start;
  height: 60px;
  padding-top: 0;
  padding-bottom: 0;
}

.card {
  display: inline-block;
  padding: 16px 8px;
  margin: var(--spacing-xxs);
  border: 1px solid var(--color-dark-gray);
  border-radius: var(--border-radius-m);
  background-color: var(--color-white);
  cursor: pointer;
  font-size: var(--font-size-s);
  box-shadow: var(--box-shadow-s);
  transition: var(--transition-ease);
  width: 50px;
  text-align: center;
  transform: translateY(0px);
  user-select: none;
}

.cards-container .card {
  margin-left: -20px;
}
.cards-container .card:first-of-type {
  margin-left: 0;
}

.card:hover {
  box-shadow: var(--box-shadow-m);
  transform: translateY(calc(var(--spacing-xxs) * -1));
}

.card.black {
  color: var(--color-black);
}

.card.red {
  color: var(--color-red);
}

.card:not(.selected) {
  transform: translateY(0px);
}

.card.selected {
  background-color: var(--color-primary-blue);
  color: var(--color-white);
  border-color: var(--color-primary-blue);
  box-shadow: var(--box-shadow-m);
  transform: translateY(calc(var(--spacing-s) * -1));
}

.card-count {
  position: absolute;
  bottom: 0;
  left: var(--spacing-xl);
  right: 0;
  font-size: var(--font-size-xxs);
  color: var(--color-medium-gray);
  text-align: left;
}

#game-messages {
  text-align: center;
  padding: var(--spacing-s);
  margin: var(--spacing-s) auto;
  line-height: var(--font-size-l);
  border-radius: var(--border-radius-s);
  font-weight: bold;
  max-width: 800px;
  width: 95%;
  min-height: 50px;
  position: fixed;
  top: 25%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: rgba(255, 255, 255, 0.95);
  box-shadow: 0 4px 8px var(--color-shadow-medium);
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease-in-out, transform 0.3s ease-in-out;
}

#game-messages.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translate(-50%, -50%) scale(1);
}

#game-messages.error {
  background-color: var(--color-error-background);
  color: var(--color-error-text);
  border: 1px solid var(--color-error-border);
}

#game-messages.info {
  background-color: var(--color-info-background);
  color: var(--color-info-text);
  border: 1px solid var(--color-info-border);
}

#controls {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: var(--color-light-gray);
  padding: var(--spacing-s) var(--spacing-l);
  box-shadow: 0 -2px 5px var(--color-shadow-light);
  z-index: 1000;
  display: flex;
  justify-content: space-around;
  gap: var(--spacing-s);
}

#controls button {
  flex: 1;
  margin: 0;
}

button {
  padding: var(--spacing-s) var(--spacing-l);
  font-size: var(--font-size-s);
  cursor: pointer;
  border: 1px solid var(--color-dark-gray);
  border-radius: var(--border-radius-s);
  transition: var(--transition-background);
}

button:hover {
  opacity: 0.9;
}

#play-button {
  background-color: var(--color-play-button);
  color: var(--color-white);
  border-color: var(--color-play-button);
}

#pass-button {
  background-color: var(--color-pass-button);
  color: var(--color-white);
  border-color: var(--color-pass-button);
}

#new-game-button {
  background-color: var(--color-new-game-button);
  color: var(--color-white);
  border-color: var(--color-new-game-button);
}

#reset-button {
  color: var(--color-darker-gray);
}

#start-game-button {
  background-color: var(--color-start-button);
  color: var(--color-white);
  border-color: var(--color-start-button);
}

button:disabled,
#play-button:disabled,
#pass-button:disabled,
#reset-button:disabled {
  background-color: var(--color-disabled-background);
  color: var(--color-disabled-text);
  cursor: not-allowed;
  border-color: var(--color-disabled-border);
}

/* AI Selection UI */
#ai-selection {
  position: absolute;
  bottom: var(--spacing-s);
  left: var(--spacing-s);
  right: var(--spacing-s);
  background-color: var(--color-light-gray);
  padding: var(--spacing-s);
  border-radius: var(--border-radius-s);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  box-shadow: var(--box-shadow-s);
}

#ai-selection label {
  font-size: var(--font-size-xs);
  font-weight: bold;
  color: var(--color-darker-gray);
}

#ai-dropdown {
  width: 100%;
  padding: var(--spacing-xs);
  border-radius: var(--border-radius-s);
  border: 1px solid var(--color-dark-gray);
  background-color: var(--color-white);
  font-size: var(--font-size-s);
  cursor: pointer;
}

#ai-dropdown:focus {
  outline: none;
  border-color: var(--color-primary-blue);
  box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
}

#ai-description {
  font-size: var(--font-size-xs);
  color: var(--color-medium-gray);
  margin-top: var(--spacing-xs);
  min-height: 3em;
}

#game-container.help {
  padding-bottom: var(--spacing-s);
  height: unset;
}

#help-container {
  margin: 0 auto;
  margin-top: var(--spacing-s);
  padding: var(--spacing-s);
  border: 1px solid var(--color-dark-gray);
  border-radius: var(--border-radius-m);
  width: 90%;
  max-width: 800px;
  background-color: var(--color-white);
  box-shadow: var(--box-shadow-s);
}

#help-container h2 {
  font-size: var(--font-size-m);
  margin-top: var(--spacing-l);
  margin-bottom: var(--spacing-s);
}

#help-container a {
  display: inline-block;
  margin-top: var(--spacing-l);
  padding: var(--spacing-s) var(--spacing-l);
  background-color: var(--color-primary-blue);
  color: var(--color-white);
  text-decoration: none;
  border-radius: var(--border-radius-s);
  transition: var(--transition-background);
}

#help-container a:hover {
  background-color: var(--color-primary-blue-hover);
}

#help-container .cards-container {
  padding: var(--spacing-m) 0;
}

#help-container #play-area .cards-container {
  padding: 0;
}

.combination-examples {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-m);
  margin-top: var(--spacing-m);
}

.combination {
  background-color: var(--color-light-gray);
  padding: var(--spacing-s) var(--spacing-xs);
  border-radius: var(--border-radius-m);
  text-align: center;
}

.combination-examples > .combination {
  padding: var(--spacing-m);
}

.combination .combination-type {
  font-size: var(--font-size-l);
  display: block;
  margin-bottom: var(--spacing-s);
}

.combination strong {
  font-size: var(--font-size-m);
  display: block;
  margin-bottom: var(--spacing-xs);
}

#try-it #play-area {
  width: 100%;
  max-width: none;
  padding: var(--spacing-m);
  margin: 0;
}

#try-it #game-content {
  padding: var(--spacing-m) 0;
}

#try-it #player-hand {
  width: 100%;
  max-width: none;
  height: unset;
  padding-bottom: var(--spacing-s);
}

#try-it .cards-container {
  background-color: transparent;
  overflow-x: visible;
}

#ai-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-m);
  margin-top: var(--spacing-m);
}

.ai {
  background-color: var(--color-light-gray);
  padding: var(--spacing-m);
  border-radius: var(--border-radius-m);
}

.ai strong {
  font-size: var(--font-size-m);
  display: block;
  margin-bottom: var(--spacing-xs);
}

@media (min-width: 576px) {
  .player-hand {
    height: 340px;
  }
  .card {
    margin-left: 0px;
  }
}

@media (min-width: 768px) {
  body {
    padding-bottom: 0;
  }

  header {
    padding: 1em 0;
  }

  .logo {
    width: 150px;
  }

  h1 {
    font-size: var(--font-size-xl);
  }

  #game-board {
    padding: var(--spacing-s) 0;
  }

  #play-area {
    margin-bottom: var(--spacing-l);
  }

  .rounds-won {
    margin-bottom: var(--spacing-s);
  }

  #players-hands {
    flex-direction: row;
    gap: var(--spacing-l);
  }

  .player-hand {
    padding: var(--spacing-m);
    height: 400px;
    width: 45%;
    padding-bottom: var(--spacing-xxl);
  }

  .player-hand .cards-container {
    flex-wrap: wrap;
    justify-content: center;
  }

  .player-hand .cards-container .card {
    margin-left: var(--spacing-xs);
  }

  #game-messages.visible {
    opacity: 1;
    pointer-events: auto;
    transform: translate(-50%, -25%) scale(1);
  }

  #ai-selection {
    bottom: calc(var(--spacing-xxl) * 1.75);
    left: var(--spacing-m);
    right: var(--spacing-m);
  }

  .help .cards-container {
    overflow-x: visible;
    justify-content: left;
    padding: 0;
  }

  .cards-container .card:first-child {
    margin-left: var(--spacing-xs);
  }

  .card {
    font-size: var(--font-size-m);
    padding: var(--spacing-m) var(--spacing-s);
    margin-left: var(--spacing-xs);
    width: 60px;
  }

  .card.selected {
    transform: translateY(calc(var(--spacing-xxs) * -1));
  }

  .combination-examples {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 992px) {
  #game-board {
    flex-grow: initial;
  }

  .player-hand {
    max-width: 550px;
  }

  .card {
    justify-content: left;
  }

  #controls {
    position: static;
    box-shadow: none;
    justify-content: center;
    gap: var(--spacing-l);
    width: auto;
    margin-top: var(--spacing-l);
    padding: 0;
    z-index: auto;
    bottom: auto;
  }

  #controls button {
    flex: none;
    margin: 0 var(--spacing-xs);
  }
}