:root {
  --green: #58cc02;
  --light-green: #61e002;
  --dark-green: #3caa3c;
  --blue: #1cb0f6;
  --white: #ffffff;
  --gray: #e5e5e5;
  --dark-gray: #4a4a4a;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  background-color: var(--white);
  color: var(--dark-gray);
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem;
  border-bottom: 1px solid var(--gray);
}

.logo {
  font-weight: 700;
  color: var(--green);
  font-size: 1.5rem;
}

.user-info {
  display: flex;
  gap: 1rem;
}

.streak, .xp {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

main {
  max-width: 800px;
  margin: 2rem auto;
  padding: 1rem;
}

.language-selector h2 {
  margin-bottom: 1.5rem;
  text-align: center;
}

.languages {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1rem;
}

.language-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem;
  border-radius: 8px;
  background-color: var(--white);
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  cursor: pointer;
  transition: transform 0.2s;
}

.language-card:hover {
  transform: translateY(-4px);
}

.language-card img {
  width: 40px;
  height: 30px;
  object-fit: cover;
}

.lesson-container {
  display: none;
}

.lesson-header {
  margin-bottom: 2rem;
}

.progress-bar {
  height: 8px;
  background-color: var(--gray);
  border-radius: 4px;
  margin-top: 0.5rem;
}

.progress {
  height: 100%;
  width: 0%;
  background-color: var(--green);
  border-radius: 4px;
  transition: width 0.3s;
}

.exercise {
  background-color: var(--white);
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.prompt {
  font-size: 1.2rem;
  margin-bottom: 1.5rem;
  font-weight: 600;
}

.options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.option {
  padding: 1rem;
  border: 2px solid var(--gray);
  border-radius: 8px;
  background-color: var(--white);
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s;
}

.option:hover {
  border-color: var(--blue);
}

.feedback {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 8px;
  text-align: center;
  font-weight: 600;
}

.correct {
  background-color: rgba(88, 204, 2, 0.1);
  color: var(--green);
}

.incorrect {
  background-color: rgba(255, 59, 48, 0.1);
  color: #ff3b30;
}

.next-btn {
  display: block;
  margin: 1rem auto 0;
  padding: 0.75rem 2rem;
  background-color: var(--green);
  color: var(--white);
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s;
}

.next-btn:hover {
  background-color: var(--light-green);
}

.hidden {
  display: none;
}