/* CSS Variables & Theme Setup */
:root {
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --bg-body: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-subtle: #eff6ff;
  --accent-emerald: #059669;
  --accent-emerald-subtle: #ecfdf5;
  --border-color: #e2e8f0;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 20px -2px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 10px 30px -4px rgba(15, 23, 42, 0.08);
  --max-width: 1120px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-body);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background-color: rgba(248, 250, 252, 0.85);
  border-bottom: 1px solid var(--border-color);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--text-main);
}

.brand-badge {
  background: linear-gradient(135deg, #2563eb, #3b82f6);
  color: #fff;
  font-size: 0.75rem;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  font-weight: 800;
  letter-spacing: 0.04em;
}

.nav-links {
  display: flex;
  gap: 20px;
  align-items: center;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s ease;
  font-family: inherit;
}

.btn-primary {
  background-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-surface);
  color: var(--text-main);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background-color: #f1f5f9;
  border-color: #cbd5e1;
}

/* Hero Section */
.hero {
  padding: 80px 0 60px;
  text-align: center;
  position: relative;
}

.badge-hero {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: var(--accent-emerald-subtle);
  color: var(--accent-emerald);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  border: 1px solid rgba(5, 150, 105, 0.2);
}

.hero-title {
  font-size: clamp(2.3rem, 5vw, 3.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 20px;
  max-width: 820px;
  margin-left: auto;
  margin-right: auto;
}

.hero-title span {
  background: linear-gradient(135deg, #1d4ed8, #059669);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-sub {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 auto 36px;
  font-weight: 400;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

/* Features Section */
.features {
  padding: 60px 0;
}

.section-head {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 48px;
}

.section-head h2 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-head p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
  display: flex;
  flex-direction: column;
}

.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: #cbd5e1;
}

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 1.4rem;
}

.icon-blue { background-color: var(--primary-subtle); color: var(--primary); }
.icon-emerald { background-color: var(--accent-emerald-subtle); color: var(--accent-emerald); }
.icon-purple { background-color: #faf5ff; color: #9333ea; }

.card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.card p {
  color: var(--text-muted);
  font-size: 0.98rem;
  flex-grow: 1;
}

/* Content & About Page Box */
.content-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 48px;
  box-shadow: var(--shadow-md);
  margin: 40px auto;
  max-width: 820px;
}

.content-box h2 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 18px;
}

.content-box p {
  font-size: 1.05rem;
  color: #334155;
  margin-bottom: 16px;
  line-height: 1.7;
}

/* Interactive Quiz Section */
.interactive-section {
  padding: 60px 0;
}

.interactive-box {
  background: linear-gradient(145deg, #ffffff, #f1f5f9);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-md);
  max-width: 780px;
  margin: 0 auto;
}

.quiz-question {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--text-main);
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.quiz-btn {
  padding: 14px 18px;
  text-align: left;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 0.98rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: inherit;
}

.quiz-btn:hover {
  background: #f8fafc;
  border-color: var(--primary);
}

.quiz-btn.active {
  background: var(--primary-subtle);
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 600;
}

.quiz-result {
  display: none;
  padding: 20px;
  border-radius: var(--radius-md);
  background-color: var(--accent-emerald-subtle);
  border: 1px solid rgba(5, 150, 105, 0.25);
  animation: fadeIn 0.3s ease;
}

.quiz-result h4 {
  color: var(--accent-emerald);
  font-size: 1.15rem;
  margin-bottom: 6px;
}

.quiz-result p {
  color: #065f46;
  font-size: 0.95rem;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-surface);
  padding: 40px 0;
  margin-top: 60px;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a:hover {
  color: var(--text-main);
  text-decoration: underline;
}

/* Modal for Contact / Imprint */
.modal-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(4px);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-backdrop.open {
  display: flex;
}

.modal-card {
  background: var(--bg-surface);
  border-radius: var(--radius-lg);
  padding: 30px;
  max-width: 480px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border-color);
}

.modal-card h3 {
  margin-bottom: 14px;
  font-size: 1.3rem;
}

.modal-card p {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

/* Responsive Queries */
@media (max-width: 768px) {
  .nav-links {
    gap: 12px;
  }
  .nav-link.hide-mobile {
    display: none;
  }
  .hero {
    padding: 50px 0 40px;
  }
  .content-box {
    padding: 24px;
  }
  .interactive-box {
    padding: 24px;
  }
  .footer-content {
    flex-direction: column;
    text-align: center;
  }
}