/* RESET & BASE */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: Arial, sans-serif;
  background-color: #0a0a0a;
  color: #e0f7fa;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px;
}

/* HEADER */
header {
  text-align: center;
  margin-bottom: 20px;
}

header h1 {
  color: #00ffff;
  font-size: 2rem;
}

header p {
  color: #b2ebf2;
}

/* SECTION LAYOUT */
section {
  max-width: 600px;
  width: 100%;
  background-color: #121212;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 0 15px rgba(0, 255, 255, 0.2);
  margin-bottom: 20px;
}

.hidden {
  display: none;
}

/* FORM ELEMENTS */
#section-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* Updated Grid Layout for Checkboxes */
#section-checkboxes {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 10px;
  justify-items: start;
}

#section-checkboxes label {
  background-color: #1a1a1a;
  padding: 10px 15px;
  border-radius: 5px;
  border: 1px solid #00bcd4;
  cursor: pointer;
  transition: background-color 0.3s;
  display: flex;
  align-items: center;
  width: 100%;
}

#section-checkboxes input {
  margin-right: 8px;
}

#section-checkboxes label:hover {
  background-color: #004d4d;
}

#session-size-options {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
  gap: 10px;
}

#start-button,
#restart-button,
#end-session-button {
  padding: 12px;
  border: none;
  background-color: #00bcd4;
  color: #fff;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s;
  width: 100%;
}

#start-button:hover,
#restart-button:hover,
#end-session-button:hover {
  background-color: #008fa3;
}

/* PROGRESS BAR */
.progress-bar {
  width: 100%;
  height: 20px;
  background-color: #1a1a1a;
  border-radius: 10px;
  overflow: hidden;
  margin-bottom: 20px;
  border: 1px solid #00bcd4;
}

#progress-fill {
  height: 100%;
  width: 0;
  background-color: #00ffff;
  transition: width 0.3s ease;
}

/* CARD CONTAINER */
#card-container {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.card {
  width: 100%;
  max-width: 400px;
  height: 250px;
  perspective: 1000px;
  margin-bottom: 20px;
  position: relative;
}

.card > div {
  width: 100%;
  height: 100%;
  border-radius: 10px;
  background-color: #1a1a1a;
  color: #e0f7fa;
  display: flex;
  justify-content: center;
  align-items: center;
  backface-visibility: hidden;
  position: absolute;
  transition: transform 0.8s;
  border: 1px solid #00bcd4;
  padding: 20px;
  text-align: center;
}

.card .back {
  transform: rotateY(180deg);
}

.card.flipped .front {
  transform: rotateY(180deg);
}

.card.flipped .back {
  transform: rotateY(360deg);
}

#flip-button {
  padding: 10px 20px;
  background-color: #00bcd4;
  border: none;
  border-radius: 5px;
  color: #fff;
  cursor: pointer;
  margin-bottom: 20px;
  transition: background-color 0.3s;
}

#flip-button:hover {
  background-color: #008fa3;
}

/* RATING BUTTONS */
#rating-buttons {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
  gap: 10px;
}

.rate-button {
  flex: 1 1 30%;
  padding: 12px;
  background-color: #004d4d;
  border: 1px solid #00bcd4;
  color: #e0f7fa;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.rate-button:hover {
  background-color: #006666;
}

/* COMPLETION SCREEN */
#completion-screen h2 {
  color: #00ffff;
  margin-bottom: 10px;
}

#completion-message {
  margin-bottom: 20px;
}