body {
  margin: 0;
  font-family: 'Inter', Arial, sans-serif;
  background: #f7f9fc;
  color: #1f2933;
}

.levels {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
}

.level {
  background: #eef2ff;
  padding: 16px 26px;
  border-radius: 999px;
  font-weight: 500;
}

header {
  background: linear-gradient(135deg, #4f46e5, #6366f1);
  color: white;
  padding: 20px 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-top {
  display: flex;
  align-items: center;
  gap: 20px;
}

.logo {
  height: 80px;
  width: auto;
}

.header-title h1 {
  font-size: 1.8rem;
  margin: 0;
  font-weight: 700;
}

.header-title p {
  font-size: 0.9rem;
  margin: 0;
  opacity: 0.9;
}

nav {
  display: flex;
  gap: 12px;
}

nav button {
  padding: 10px 24px;
  border-radius: 999px;
  border: none;
  background-color: rgba(255, 255, 255, 0.2);
  color: white;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
}

nav button:hover {
  background-color: rgba(255, 255, 255, 0.3);
}

nav button.nav-active {
  background-color: white !important;
  color: #4f46e5 !important;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

main {
  padding: 0;
  min-height: calc(100vh - 120px);
  display: flex;
}

.uitleg-column {
  width: 35%;
  background: white;
  padding: 40px;
  border-right: 1px solid #e2e8f0;
  overflow-y: auto;
}

.oefening-column {
  width: 65%;
  padding: 60px;
  background: #f8fafc;
  display: flex;
  flex-direction: column;
  align-items: center;
}


.text-center { text-align: center; }


.grid-main {
    display: flex;
    gap: 20px;
    align-items: start;
}

.formule {
  font-size: 1.5rem;
  font-weight: 600;
  margin: 1.5rem 0;
  color: #1f2933;
}

.feedback {
  margin-top: 10px;
  font-weight: 600;
  min-height: 24px;
}

.fb-correct { color: #10b981; }
.fb-incorrect { color: #ef4444; }

.uit { display: none !important; }

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 32px;
  margin: 40px 0;
}

.card {
  background: white;
  border-radius: 20px;
  padding: 30px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  transition: transform 0.2s;
}

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

.container {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  padding: 40px 0;
}

.a-card {
  display: flex;
  align-items: center;
  justify-content: center;
  background: white;
  padding: 20px 40px;
  border-radius: 16px;
  font-weight: 700;
  font-size: 1.2rem;
  color: #4f46e5;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
  transition: all 0.2s;
}

.a-card:hover {
  background: #4f46e5;
  color: white;
  transform: scale(1.05);
}

footer {
  background: #1e293b;
  color: #94a3b8;
  padding: 40px;
  text-align: center;
  margin-top: auto;
}

footer a {
  color: #6366f1;
  font-weight: 600;
}
section {
	text-align:center:
}

.opdracht {
    display: grid;
    grid-template-rows: 40px auto;

    .mode {

        button{
            padding: 0.5rem 0.75rem;
            border-radius: 16px;}
        align-items: center;
        justify-content: center;
        display:flex;
        }

    .zelf-oefenen {
        display: flex;
        flex-direction: column;
        align-items: center;

        .formule{
            color: black;
            font-size: 1.5em;
            margin: 16px 0;}

        .invul-feedback{
            input {
                font-size: larger;
                padding: 10px 0 10px 10px;
                border: solid 1px blue;
                border-right: none;
            }
            button{
                background-color: blue;
                font-size: larger;
                border: solid 1px blue;
                border-left: none;
                padding: 10px 10px 10px 5px;

            }
            button:hover{
                background: aqua;}

            .feedback{
                margin-top: 10px;
                color: black;}

            .correct{
                color: lawngreen;}

            .incorrect{
                color: red;}
        }
    }
}

.invul-feedback h4 {
    color: #1E90FF;
    font-weight: bold;
    font-size: 1.2em;
    margin-bottom: 8px;
}


#klaar h3 {
    color: darkorange;
    font-weight: bold,
    font-size: 1.5em;
    text-align: center;
    margin-top: 20px;
}

.uit {
    display: none;}