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

:root {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --success: #22c55e;
  --error: #ef4444;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--primary);
}

.logo svg {
  color: var(--primary);
}

nav {
  display: flex;
  gap: 24px;
}

nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

nav a:hover {
  color: var(--primary);
}

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
  color: white;
  padding: 60px 0;
  text-align: center;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.hero p {
  font-size: 1.125rem;
  opacity: 0.9;
  margin-bottom: 24px;
}

.trust-badges {
  display: flex;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
}

.trust-badges span {
  background: rgba(255,255,255,0.15);
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
}

/* Converters Section */
.converters {
  padding: 48px 0;
}

.converters h2 {
  text-align: center;
  font-size: 1.75rem;
  margin-bottom: 16px;
}

.section-intro {
  text-align: center;
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 32px;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

.converter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin-bottom: 32px;
}

.converter-btn {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.converter-btn:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.converter-btn.active {
  border-color: var(--primary);
  background: #eef2ff;
}

.converter-btn .icon {
  font-size: 2rem;
}

.converter-btn .format {
  font-weight: 600;
  color: var(--text);
}

.converter-btn .desc {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Converter Area */
.converter-area {
  max-width: 600px;
  margin: 0 auto;
}

.drop-zone {
  background: var(--surface);
  border: 3px dashed var(--border);
  border-radius: 16px;
  padding: 60px 40px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
}

.drop-zone:hover,
.drop-zone.dragover {
  border-color: var(--primary);
  background: #eef2ff;
}

.drop-content .upload-icon {
  color: var(--text-muted);
  margin-bottom: 16px;
}

.drop-text {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.drop-subtext {
  color: var(--text-muted);
  margin-bottom: 12px;
}

.file-types {
  font-size: 0.875rem;
  color: var(--text-muted);
  background: var(--bg);
  display: inline-block;
  padding: 6px 12px;
  border-radius: 6px;
}

/* Progress Area */
.progress-area {
  background: var(--surface);
  border-radius: 16px;
  padding: 32px;
  text-align: center;
}

.file-info {
  display: flex;
  justify-content: space-between;
  margin-bottom: 16px;
  font-size: 0.875rem;
}

.file-name {
  font-weight: 500;
  color: var(--text);
}

.file-size {
  color: var(--text-muted);
}

.progress-bar {
  background: var(--border);
  border-radius: 8px;
  height: 8px;
  overflow: hidden;
  margin-bottom: 16px;
}

.progress-fill {
  background: linear-gradient(90deg, var(--primary), #7c3aed);
  height: 100%;
  width: 0%;
  transition: width 0.3s;
  border-radius: 8px;
}

.status-text {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Result Area */
.result-area {
  background: var(--surface);
  border-radius: 16px;
  padding: 48px 32px;
  text-align: center;
}

.success-icon {
  width: 64px;
  height: 64px;
  background: var(--success);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 700;
  margin: 0 auto 24px;
}

.result-area h3 {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.result-area > p {
  color: var(--text-muted);
  margin-bottom: 24px;
}

.download-btn {
  display: inline-block;
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
  color: white;
  padding: 14px 32px;
  border-radius: 10px;
  text-decoration: none;
  font-weight: 600;
  margin-bottom: 16px;
  transition: transform 0.2s;
}

.download-btn:hover {
  transform: translateY(-2px);
}

.convert-another-btn {
  display: block;
  margin: 0 auto;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.875rem;
}

.convert-another-btn:hover {
  color: var(--primary);
}

/* Error Area */
.error-area {
  background: var(--surface);
  border-radius: 16px;
  padding: 48px 32px;
  text-align: center;
}

.error-icon {
  width: 64px;
  height: 64px;
  background: var(--error);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 700;
  margin: 0 auto 24px;
}

.error-area h3 {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.error-area > p {
  color: var(--text-muted);
  margin-bottom: 24px;
}

.try-again-btn {
  background: var(--primary);
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 500;
}

.try-again-btn:hover {
  background: var(--primary-hover);
}

/* Features Section */
.features {
  padding: 60px 0;
  background: var(--surface);
}

.features h2 {
  text-align: center;
  font-size: 1.75rem;
  margin-bottom: 16px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  margin-top: 40px;
}

.feature-card {
  background: var(--bg);
  padding: 24px;
  border-radius: 12px;
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.feature-card h3 {
  font-size: 1.125rem;
  margin-bottom: 12px;
  color: var(--primary);
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.9375rem;
  line-height: 1.7;
}

/* Ad Section */
.ad-section {
  background: var(--surface);
  padding: 24px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.ad-placeholder {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  height: 100px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* How It Works */
.how-it-works {
  padding: 60px 0;
  background: var(--surface);
}

.how-it-works h2 {
  text-align: center;
  font-size: 1.75rem;
  margin-bottom: 40px;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 32px;
}

.step {
  text-align: center;
}

.step-number {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 700;
  margin: 0 auto 16px;
}

.step h3 {
  margin-bottom: 8px;
}

.step p {
  color: var(--text-muted);
  font-size: 0.9375rem;
}

/* FAQ */
.faq {
  padding: 60px 0;
}

.faq h2 {
  text-align: center;
  font-size: 1.75rem;
  margin-bottom: 40px;
}

.faq-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.faq-item {
  background: var(--surface);
  padding: 24px;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.faq-item h3 {
  font-size: 1rem;
  margin-bottom: 8px;
}

.faq-item p {
  color: var(--text-muted);
  font-size: 0.9375rem;
}

/* Footer */
footer {
  background: var(--text);
  color: white;
  padding: 40px 0 32px;
}

footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-content {
  margin-bottom: 16px;
}

.footer-tagline {
  color: rgba(255,255,255,0.6);
  font-size: 0.875rem;
  margin-top: 8px;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  color: rgba(255,255,255,0.7);
  text-decoration: none;
  font-size: 0.875rem;
}

.footer-links a:hover {
  color: white;
}

/* Mobile */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 1.75rem;
  }

  .hero p {
    font-size: 1rem;
  }

  nav {
    display: none;
  }

  .converter-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .drop-zone {
    padding: 40px 20px;
  }

  footer .container {
    flex-direction: column;
    text-align: center;
  }

  .footer-content {
    margin-bottom: 16px;
  }
}