* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background-color: #f0f3f8;
  color: #2c3e50;
  display: flex;
  justify-content: center;
}

.app-container {
  width: 100%;
  max-width: 480px;
  min-height: 100vh;
  background-color: #ffffff;
  box-shadow: 0 0 15px rgba(0,0,0,0.08);
  display: flex;
  flex-direction: column;
}

/* Header Tema Biru Indigo / Violet */
.header {
  background: linear-gradient(135deg, #4834d4, #686de0);
  color: white;
  text-align: center;
  padding: 20px 15px;
}

.header h1 {
  font-size: 1.4rem;
  margin-bottom: 5px;
}

.header p {
  font-size: 0.88rem;
  opacity: 0.95;
}

.nav-menu {
  display: flex;
  background-color: #f0edff;
  border-bottom: 2px solid #dcd6f7;
}

.nav-btn {
  flex: 1;
  padding: 12px 2px;
  border: none;
  background: none;
  font-size: 0.88rem;
  font-weight: bold;
  color: #4834d4;
  cursor: pointer;
  transition: 0.3s;
}

.nav-btn.active {
  background-color: #ffffff;
  color: #4834d4;
  border-bottom: 3px solid #4834d4;
}

.content {
  padding: 15px;
  flex: 1;
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

.card {
  background-color: #ffffff;
  border-radius: 12px;
  padding: 15px;
  margin-bottom: 15px;
  border: 1px solid #e1e8f0;
  box-shadow: 0 2px 5px rgba(0,0,0,0.04);
}

.card h2 {
  font-size: 1.05rem;
  color: #4834d4;
  margin-bottom: 10px;
}

.card p {
  font-size: 0.92rem;
  line-height: 1.4;
}

.example-box {
  background-color: #f0edff;
  border-left: 4px solid #4834d4;
  padding: 10px;
  border-radius: 6px;
  margin-top: 8px;
  font-size: 0.9rem;
}

/* Tabel Frekuensi */
.simple-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 5px;
  font-size: 0.9rem;
}

.simple-table th, .simple-table td {
  border: 1px solid #dcd6f7;
  padding: 8px;
  text-align: center;
}

.simple-table th {
  background-color: #4834d4;
  color: white;
}

/* Form Input Simulasi */
.input-grid {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 8px;
}

.input-group {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.input-group label {
  font-weight: bold;
  font-size: 0.9rem;
}

.input-group input {
  width: 70px;
  padding: 6px;
  border: 1px solid #b2bec3;
  border-radius: 6px;
  text-align: center;
  font-weight: bold;
}

/* Piktogram Style */
.pictogram-box {
  display: flex;
  flex-direction: column;
  gap: 8px;
  background-color: #f0edff;
  padding: 10px;
  border-radius: 8px;
  font-size: 0.9rem;
}

.pic-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.pic-label {
  width: 80px;
  font-weight: bold;
}

.pic-icons {
  font-size: 1.2rem;
  letter-spacing: 2px;
}

/* Diagram Batang Style */
.bar-chart-box {
  display: flex;
  align-items: flex-end;
  justify-content: space-around;
  height: 150px;
  background-color: #f0edff;
  padding: 10px;
  border-radius: 8px;
  border-bottom: 3px solid #4834d4;
}

.bar-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  height: 100%;
  justify-content: flex-end;
  width: 60px;
}

.bar-inner {
  width: 35px;
  background: linear-gradient(to top, #4834d4, #686de0);
  border-radius: 4px 4px 0 0;
  transition: height 0.3s ease;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  color: white;
  font-size: 0.75rem;
  font-weight: bold;
  padding-top: 2px;
}

.bar-title {
  font-size: 0.75rem;
  font-weight: bold;
  margin-top: 6px;
  color: #2c3e50;
  text-align: center;
}

/* Kuis Style */
.quiz-header {
  font-size: 0.85rem;
  color: #777;
  margin-bottom: 8px;
}

.question {
  font-weight: bold;
  font-size: 0.98rem;
  margin-bottom: 12px;
}

.quiz-visual-card {
  background-color: #f0edff;
  border: 1px dashed #4834d4;
  padding: 10px;
  border-radius: 8px;
  margin-bottom: 12px;
}

.options-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option-btn {
  padding: 12px;
  border: 1px solid #4834d4;
  background-color: #fff;
  color: #4834d4;
  border-radius: 8px;
  font-size: 0.95rem;
  text-align: left;
  cursor: pointer;
  transition: 0.2s;
}

.option-btn.correct {
  background-color: #2ecc71;
  color: white;
  border-color: #2ecc71;
}

.option-btn.wrong {
  background-color: #ff7675;
  color: white;
  border-color: #ff7675;
}

.feedback {
  margin-top: 10px;
  font-weight: bold;
  text-align: center;
}

.action-btn {
  width: 100%;
  padding: 12px;
  margin-top: 15px;
  background-color: #4834d4;
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  font-size: 0.98rem;
  cursor: pointer;
}

.score-box {
  text-align: center;
  font-size: 3rem;
  font-weight: bold;
  color: #2ecc71;
  margin: 15px 0;
}