:root {
    --primary: #1f2937; --primary-light: #374151; --accent: #f59e0b; --accent-dark: #d97706;
    --bg: #f9fafb; --bg-light: #ffffff; --border: #e5e7eb; --text-secondary: #6b7280;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-korean: 'Pretendard', 'Inter', -apple-system, sans-serif;
    --spacing-2: 16px; --spacing-3: 24px; --spacing-4: 32px; --spacing-5: 48px; --spacing-6: 64px; --spacing-7: 96px;
    --h1-size: 40px; --h2-size: 28px; --h3-size: 20px;
    --transition-fast: 100ms ease;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: var(--font-sans); font-size: 16px; line-height: 1.6; color: var(--primary); background-color: var(--bg); }

h1, h2, h3, h4, h5, h6 { font-family: var(--font-korean); font-weight: 700; line-height: 1.3; margin-bottom: var(--spacing-3); }
h1, .headline-1 { font-size: var(--h1-size); letter-spacing: -0.02em; }
h2, .headline-2 { font-size: var(--h2-size); }
h3, .headline-3 { font-size: var(--h3-size); }

p { margin-bottom: var(--spacing-2); }
a { color: var(--accent); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--accent-dark); }
em { font-style: italic; color: var(--accent); }

.container { max-width: 1200px; margin: 0 auto; padding: var(--spacing-3); }

.navbar { background: var(--bg-light); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 100; box-shadow: 0 1px 3px rgba(0,0,0,0.1); }
.nav-brand { font-size: 20px; font-weight: 700; color: var(--primary); font-family: var(--font-korean); }
.nav-inner { display: flex; justify-content: space-between; align-items: center; }
.lang-switcher { display: flex; gap: 4px; align-items: center; flex-wrap: wrap; }
.lang-btn { padding: 4px 9px; background: transparent; border: 1px solid var(--border); border-radius: 4px; cursor: pointer; font-size: 11px; color: var(--text-secondary); transition: all var(--transition-fast); font-family: var(--font-sans); }
.lang-btn:hover { border-color: var(--accent); color: var(--accent); }
.lang-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; }
.lang-select { padding: 5px 10px; border: 1px solid var(--border); border-radius: 6px; font-size: 13px; cursor: pointer; background: var(--bg-light); color: var(--primary); font-family: var(--font-sans); outline: none; }
.lang-select:focus { border-color: var(--accent); }

.hero { background: linear-gradient(135deg, var(--bg-light) 0%, var(--bg) 100%); padding: var(--spacing-7) var(--spacing-3); text-align: center; }
.hero-content { animation: fadeInUp 0.6s ease-out; }
.hero .headline-1 { margin-bottom: var(--spacing-3); max-width: 700px; margin-left: auto; margin-right: auto; }
.subheadline { font-size: 18px; color: var(--primary-light); max-width: 600px; margin-left: auto; margin-right: auto; margin-bottom: var(--spacing-5); line-height: 1.8; }

.btn { display: inline-block; padding: var(--spacing-2) var(--spacing-4); border: none; border-radius: 6px; font-size: 16px; font-weight: 600; font-family: var(--font-sans); cursor: pointer; transition: all var(--transition-fast); text-decoration: none; }
.btn-primary { background: var(--accent); color: white; }
.btn-primary:hover { background: var(--accent-dark); transform: scale(1.02); }
.btn-large { padding: var(--spacing-3) var(--spacing-6); font-size: 18px; }
.btn-block { display: block; width: 100%; }

.pain-section { padding: var(--spacing-7) var(--spacing-3); background: var(--bg); }
.section-header { text-align: center; margin-bottom: var(--spacing-5); }
.pain-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: var(--spacing-4); }
.card { background: var(--bg-light); border: 1px solid var(--border); border-radius: 8px; padding: var(--spacing-4); animation: fadeInUp 0.6s ease-out 0.1s both; }
.pain-card { box-shadow: 0 1px 3px rgba(0,0,0,0.08); transition: box-shadow var(--transition-fast), transform var(--transition-fast); }
.pain-card:hover { box-shadow: 0 4px 12px rgba(0,0,0,0.12); transform: translateY(-4px); }
.card-title { font-size: 18px; font-weight: 600; margin-bottom: var(--spacing-2); color: var(--primary); }
.card-body { font-size: 15px; line-height: 1.7; color: var(--primary-light); }

.solution-section { padding: var(--spacing-7) var(--spacing-3); background: var(--bg-light); }
.solution-content { max-width: 800px; margin: 0 auto; }
.solution-intro { font-size: 18px; margin-bottom: var(--spacing-3); }
.code-block { background: var(--primary); color: #d1d5db; padding: var(--spacing-4); border-radius: 8px; overflow-x: auto; margin: var(--spacing-4) 0; font-family: 'Monaco', 'Menlo', monospace; font-size: 14px; line-height: 1.6; white-space: pre; }
.solution-list { list-style: none; margin: var(--spacing-4) 0; }
.solution-list li { padding-left: var(--spacing-4); margin-bottom: var(--spacing-2); position: relative; }
.solution-list li:before { content: "→"; position: absolute; left: 0; color: var(--accent); font-weight: 600; }

.social-proof-section { padding: var(--spacing-7) var(--spacing-3); background: var(--bg); }
.quote-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--spacing-4); }
.quote-card { border-left: 4px solid var(--accent); box-shadow: 0 1px 3px rgba(0,0,0,0.08); animation: fadeInUp 0.6s ease-out 0.2s both; }
.quote-text { font-size: 16px; font-style: italic; color: var(--primary); margin-bottom: var(--spacing-2); }
.quote-attr { font-size: 14px; color: var(--text-secondary); font-weight: 500; }

.presale-section { padding: var(--spacing-7) var(--spacing-3); background: linear-gradient(135deg, var(--primary) 0%, #111827 100%); color: var(--bg-light); text-align: center; }
.presale-content { max-width: 600px; margin: 0 auto; }
.presale-section .headline-2 { color: var(--bg-light); margin-bottom: var(--spacing-4); }
.presale-intro { font-size: 18px; color: #d1d5db; margin-bottom: var(--spacing-2); }
.presale-detail { font-size: 16px; color: #9ca3af; margin-bottom: var(--spacing-5); }

.footer { background: var(--primary); color: var(--bg-light); padding: var(--spacing-4) var(--spacing-3); text-align: center; font-size: 14px; border-top: 1px solid rgba(255,255,255,0.1); }
.footer a { color: var(--accent); }

.modal { display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0; z-index: 1000; }
.modal.active { display: flex; animation: fadeIn 0.2s ease-out; }
.modal-overlay { flex: 1; background: rgba(0,0,0,0.5); }
.modal-content { width: 100%; max-width: 420px; background: var(--bg-light); border-radius: 12px; box-shadow: 0 20px 60px rgba(0,0,0,0.3); display: flex; flex-direction: column; animation: slideUp 0.3s ease-out; margin: auto; }
.modal-header { padding: var(--spacing-4); border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; }
.modal-header h3 { margin: 0; font-size: 20px; }
.modal-close { background: none; border: none; font-size: 28px; color: var(--primary); cursor: pointer; padding: 0; width: 32px; height: 32px; display: flex; align-items: center; justify-content: center; }
.presale-form { padding: var(--spacing-4); display: flex; flex-direction: column; gap: var(--spacing-3); }
.form-group { display: flex; flex-direction: column; }
.form-group label { font-weight: 600; margin-bottom: 6px; color: var(--primary); font-size: 14px; }
.form-group input[type="email"], .form-group input[type="text"] { padding: var(--spacing-2); border: 1px solid var(--border); border-radius: 6px; font-size: 16px; font-family: var(--font-sans); transition: border-color var(--transition-fast); }
.form-group input:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px rgba(245,158,11,0.1); }
.form-group.checkbox { flex-direction: row; align-items: flex-start; gap: var(--spacing-2); margin-bottom: var(--spacing-2); }
.form-group.checkbox input { margin-top: 4px; cursor: pointer; }
.form-group.checkbox label { margin: 0; font-weight: 400; line-height: 1.5; }
.form-fallback { text-align: center; font-size: 14px; color: var(--text-secondary); margin-top: var(--spacing-3); padding-top: var(--spacing-3); border-top: 1px solid var(--border); }

@keyframes fadeInUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { transform: translateY(40px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

@media (max-width: 768px) {
    :root { --h1-size: 32px; --h2-size: 24px; --spacing-7: 48px; }
    .container { padding: var(--spacing-2); }
    .hero { padding: var(--spacing-5) var(--spacing-2); }
    .pain-grid, .quote-grid { grid-template-columns: 1fr; }
    .pain-section, .solution-section, .social-proof-section, .presale-section { padding: var(--spacing-5) var(--spacing-2); }
    .modal-content { max-width: 90%; margin: var(--spacing-3); }
}

@media (max-width: 480px) {
    :root { --h1-size: 28px; --h2-size: 20px; --spacing-7: 32px; --spacing-6: 48px; }
    .btn-large { padding: var(--spacing-2) var(--spacing-4); font-size: 16px; }
    .subheadline { font-size: 16px; }
    .code-block { font-size: 12px; padding: var(--spacing-3); }
    .modal-content { border-radius: 16px; margin-bottom: 0; }
}