/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, #eef2ff 0%, #ffffff 50%, #f5f3ff 100%);
  color: #111827;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* Layout */
.container { max-width: 80rem; margin: 0 auto; padding: 0 1rem; }
.max-w-3xl { max-width: 48rem; }
.max-w-5xl { max-width: 64rem; }

/* Header */
header { background: rgba(255,255,255,0.8); backdrop-filter: blur(8px); border-bottom: 1px solid #f3f4f6; position: sticky; top: 0; z-index: 50; }
nav { display: flex; align-items: center; justify-content: space-between; padding: 1rem; }
.nav-logo { display: flex; align-items: center; gap: 0.5rem; font-weight: 700; font-size: 1.25rem; }
.nav-logo svg { width: 2rem; height: 2rem; color: #4f46e5; }
.nav-logo span { color: #4f46e5; }
.nav-links { display: flex; gap: 1.5rem; }
.nav-links a { color: #4b5563; font-weight: 500; font-size: 0.875rem; transition: color 0.2s; }
.nav-links a:hover { color: #4f46e5; }

/* Hero */
.hero { text-align: center; padding: 4rem 1rem; }
.hero h1 { font-size: 2.5rem; font-weight: 800; margin-bottom: 1.5rem; line-height: 1.2; }
.hero h1 span { color: #4f46e5; }
.hero p { font-size: 1.125rem; color: #4b5563; max-width: 42rem; margin: 0 auto 2rem; }
.hero-badges { display: flex; flex-wrap: wrap; justify-content: center; gap: 1rem; font-size: 0.875rem; color: #6b7280; }
.hero-badges span { display: flex; align-items: center; gap: 0.25rem; }
.hero-badges svg { width: 1rem; height: 1rem; color: #22c55e; }

/* Section */
section { padding: 0 1rem 5rem; }

/* Card */
.card { background: white; border-radius: 1rem; box-shadow: 0 10px 15px -3px rgba(0,0,0,0.1); padding: 1.5rem; border: 1px solid #f9fafb; }
.card h2 { font-size: 1.5rem; font-weight: 700; text-align: center; margin-bottom: 1.5rem; }
.text-center { text-align: center; }

/* Converter */
.converter-card { max-width: 48rem; margin: 0 auto; }
.drop-zone { border: 2px dashed #c7d2fe; border-radius: 0.75rem; padding: 3rem; text-align: center; cursor: pointer; transition: all 0.2s; }
.drop-zone:hover { border-color: #6366f1; background: #eef2ff; }
.drop-zone.dragover { border-color: #6366f1; background: #eef2ff; }
.drop-zone svg { width: 3rem; height: 3rem; margin: 0 auto 1rem; color: #a5b4fc; }
.drop-zone p { color: #374151; font-weight: 500; margin-bottom: 0.25rem; }
.drop-zone p span { color: #4f46e5; }
.drop-zone small { color: #9ca3af; font-size: 0.875rem; }

/* File Info */
.file-info { display: none; margin-bottom: 1.5rem; padding: 1rem; background: #eef2ff; border-radius: 0.75rem; }
.file-info.show { display: block; }
.file-info-inner { display: flex; align-items: center; justify-content: space-between; }
.file-info-left { display: flex; align-items: center; gap: 0.75rem; }
.file-icon { width: 2.5rem; height: 2.5rem; background: #c7d2fe; border-radius: 0.5rem; display: flex; align-items: center; justify-content: center; }
.file-icon svg { width: 1.25rem; height: 1.25rem; color: #4f46e5; }
.file-name { font-weight: 500; color: #111827; }
.file-size { font-size: 0.875rem; color: #6b7280; }
.remove-btn { color: #9ca3af; transition: color 0.2s; }
.remove-btn:hover { color: #ef4444; }

/* Inputs */
.form-group { margin-bottom: 1.5rem; }
.form-group label { display: block; font-weight: 500; color: #374151; margin-bottom: 0.5rem; font-size: 0.875rem; }
.form-group input { width: 100%; padding: 0.75rem 1rem; border: 1px solid #e5e7eb; border-radius: 0.5rem; font-size: 1rem; transition: all 0.2s; }
.form-group input:focus { outline: none; border-color: #6366f1; box-shadow: 0 0 0 3px rgba(99,102,241,0.1); }

/* Button */
.btn-primary { background: #4f46e5; color: white; font-weight: 500; padding: 0.75rem 1.5rem; border-radius: 0.5rem; border: none; cursor: pointer; transition: background 0.2s; width: 100%; display: flex; align-items: center; justify-content: center; gap: 0.5rem; font-size: 1rem; }
.btn-primary:hover:not(:disabled) { background: #4338ca; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-primary svg { width: 1.25rem; height: 1.25rem; }

/* Progress */
.progress-container { display: none; margin-top: 1.5rem; }
.progress-container.show { display: block; }
.progress-header { display: flex; justify-content: space-between; margin-bottom: 0.5rem; }
.progress-text { font-size: 0.875rem; color: #4b5563; }
.progress-percent { font-size: 0.875rem; font-weight: 500; color: #4f46e5; }
.progress-bar { width: 100%; background: #f3f4f6; border-radius: 9999px; height: 0.5rem; }
.progress-bar-inner { background: #4f46e5; height: 0.5rem; border-radius: 9999px; transition: width 0.3s; }

/* Download Section */
.download-section { display: none; margin-top: 1.5rem; padding: 1.5rem; background: #f0fdf4; border-radius: 0.75rem; border: 1px solid #bbf7d0; }
.download-section.show { display: block; }
.download-section svg { width: 3rem; height: 3rem; margin: 0 auto 0.75rem; color: #22c55e; }
.download-section h3 { font-size: 1.125rem; font-weight: 600; color: #166534; margin-bottom: 0.25rem; }
.download-section p { font-size: 0.875rem; color: #16a34a; margin-bottom: 1rem; }
.download-btn { display: inline-flex; align-items: center; gap: 0.5rem; background: #16a34a; color: white; font-weight: 500; padding: 0.75rem 2rem; border-radius: 0.5rem; border: none; cursor: pointer; transition: background 0.2s; font-size: 1rem; }
.download-btn:hover { background: #15803d; }

/* Error */
.error-section { display: none; margin-top: 1.5rem; padding: 1rem; background: #fef2f2; border-radius: 0.75rem; border: 1px solid #fecaca; }
.error-section.show { display: block; }
.error-section p { color: #dc2626; font-size: 0.875rem; text-align: center; }

/* Features */
.features-grid { display: grid; gap: 2rem; }
@media (min-width: 768px) { .features-grid { grid-template-columns: repeat(3, 1fr); } }
.feature-icon { width: 3.5rem; height: 3.5rem; background: #e0e7ff; border-radius: 1rem; display: flex; align-items: center; justify-content: center; margin: 0 auto 1rem; }
.feature-icon svg { width: 1.75rem; height: 1.75rem; color: #4f46e5; }
.feature h3 { font-size: 1.125rem; font-weight: 600; margin-bottom: 0.5rem; }
.feature p { color: #4b5563; font-size: 0.875rem; }

/* FAQ */
details.card { cursor: pointer; }
details.card[open] summary .faq-icon { transform: rotate(180deg); }
summary { display: flex; align-items: center; justify-content: space-between; list-style: none; font-weight: 600; }
summary::-webkit-details-marker { display: none; }
.faq-icon { width: 1.25rem; height: 1.25rem; color: #6b7280; transition: transform 0.2s; }
details.card p { margin-top: 1rem; color: #4b5563; font-size: 0.875rem; }

/* Footer */
footer { background: white; border-top: 1px solid #f3f4f6; padding: 2rem 1rem; text-align: center; }
footer p { font-size: 0.875rem; color: #6b7280; }

/* Responsive */
@media (min-width: 640px) {
  .hero h1 { font-size: 3rem; }
  .drop-zone { padding: 4rem; }
}
@media (min-width: 768px) {
  .hero h1 { font-size: 3.5rem; }
}