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

:root {
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #eff6ff;
  --color-text: #1a1a1a;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --color-bg: #ffffff;
  --color-bg-alt: #f8fafc;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.08);
  --transition: 0.2s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Apple SD Gothic Neo', 'Malgun Gothic', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background-color: #fafafa;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

ul,
ol {
  list-style: none;
}

/* ===== Header ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition), box-shadow var(--transition);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-primary);
}

.nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.nav a:hover,
.nav a:focus {
  color: var(--color-text);
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  background: none;
  border: none;
  cursor: pointer;
  border-radius: 8px;
}

.menu-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  transition: transform var(--transition), opacity var(--transition);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.25rem;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: background var(--transition), color var(--transition), transform 0.15s ease, border-color var(--transition);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

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

.btn-secondary {
  background: var(--color-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-bg-alt);
  border-color: #cbd5e1;
}

.btn-header {
  padding: 0.5rem 1rem;
  font-size: 0.85rem;
}

.btn-large {
  padding: 0.9rem 1.75rem;
  font-size: 1rem;
  min-width: 220px;
}

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 7rem 1.5rem 4rem;
  background: linear-gradient(180deg, #ffffff 0%, var(--color-bg-alt) 100%);
}

.hero-inner {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
}

.hero-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-primary);
  letter-spacing: 0.02em;
  margin-bottom: 1rem;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
}

.hero-desc {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-bottom: 2rem;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

/* ===== Sections ===== */
.section {
  padding: 5rem 1.5rem;
  background: var(--color-bg);
}

.section:nth-child(even) {
  background: var(--color-bg-alt);
}

.section-inner {
  max-width: 1100px;
  margin: 0 auto;
}

.section-title {
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.75rem;
}

.section-desc {
  font-size: 1rem;
  color: var(--color-text-muted);
  text-align: center;
  margin-bottom: 3rem;
}

/* ===== Features ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.feature-card {
  padding: 2rem 1.5rem;
  background: var(--color-bg);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  transition: box-shadow var(--transition), border-color var(--transition), transform var(--transition);
}

.feature-card:hover {
  box-shadow: var(--shadow-md);
  border-color: #cbd5e1;
  transform: translateY(-2px);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ===== Value ===== */
.value-list {
  max-width: 560px;
  margin: 0 auto;
}

.value-list li {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.value-list li:last-child {
  border-bottom: none;
}

.value-list strong {
  font-size: 1rem;
  font-weight: 600;
}

.value-list span {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ===== Flow ===== */
.flow-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.flow-step {
  padding: 2rem 1.5rem;
  background: var(--color-bg);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  text-align: center;
}

.flow-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-size: 1rem;
  font-weight: 700;
  border-radius: 50%;
  margin-bottom: 1rem;
}

.flow-step h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}

.flow-step p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* ===== Brand ===== */
.brand .section-inner {
  max-width: 560px;
  margin: 0 auto;
}

.brand-text {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text-muted);
  text-align: center;
}

/* ===== CTA ===== */
.cta {
  background: linear-gradient(180deg, var(--color-bg-alt) 0%, #ffffff 100%);
}

.cta-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  margin-bottom: 1rem;
}

.cta-note {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* ===== Footer ===== */
.footer {
  padding: 3rem 1.5rem;
  background: var(--color-text);
  color: rgba(255, 255, 255, 0.8);
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  text-align: center;
}

.footer-logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 1rem;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.footer-nav a {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.7);
  transition: color var(--transition);
}

.footer-nav a:hover,
.footer-nav a:focus {
  color: #fff;
}

.footer-copy {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.5);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav {
    display: none;
  }

  .nav.is-open {
    display: flex;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    padding: 1.25rem 1.5rem 1.5rem;
    background: #fff;
    border-bottom: 1px solid var(--color-border);
    gap: 1rem;
    box-shadow: var(--shadow-md);
  }

  .nav.is-open a {
    width: 100%;
  }

  .menu-toggle {
    display: flex;
  }

  .hero {
    padding: 6rem 1.25rem 3rem;
  }

  .section {
    padding: 3.5rem 1.25rem;
  }

  .section-desc {
    margin-bottom: 2rem;
  }

  .cta-buttons {
    flex-direction: column;
    align-items: center;
  }

  .btn-large {
    width: 100%;
    max-width: 280px;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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