/* =====================================================
   CSS Custom Properties (Design Tokens)
   ===================================================== */
:root {
  --color-primary:     #1a1a2e;
  --color-accent:      #0f3460;
  --color-highlight:   #e94560;
  --color-bg:          #ffffff;
  --color-bg-alt:      #f7f7f9;
  --color-text:        #1a1a2e;
  --color-text-muted:  #6b7280;
  --color-border:      #e5e7eb;

  --font-family:       'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
  --font-size-base:    16px;
  --font-size-sm:      14px;
  --font-size-lg:      20px;
  --font-size-xl:      28px;
  --font-size-2xl:     40px;
  --font-size-3xl:     56px;

  --line-height-base:  1.7;
  --line-height-tight: 1.3;

  --spacing-xs:  8px;
  --spacing-sm:  16px;
  --spacing-md:  24px;
  --spacing-lg:  48px;
  --spacing-xl:  80px;
  --spacing-2xl: 120px;

  --radius-sm:   4px;
  --radius-md:   8px;
  --radius-lg:   16px;

  --shadow-sm:   0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md:   0 4px 12px rgba(0,0,0,0.10), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg:   0 10px 30px rgba(0,0,0,0.12), 0 4px 8px rgba(0,0,0,0.06);

  --transition:  0.25s ease;
  --container-max: 1120px;
}

/* =====================================================
   Reset & Base
   ===================================================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: var(--font-size-base); scroll-behavior: smooth; }
body {
  font-family: var(--font-family);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: var(--line-height-base);
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* =====================================================
   Layout
   ===================================================== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* =====================================================
   Typography helpers
   ===================================================== */
.section-title {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-md);
  text-align: center;
}
.section-lead {
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
  text-align: center;
  margin-bottom: var(--spacing-lg);
  line-height: var(--line-height-base);
}

/* =====================================================
   Button
   ===================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 36px;
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
}
.btn:hover  { opacity: 0.88; transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn:active { opacity: 1;    transform: translateY(0);    box-shadow: none; }

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

/* =====================================================
   Header
   ===================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  gap: var(--spacing-md);
}
.logo {
  font-size: var(--font-size-xl);
  font-weight: 800;
  color: var(--color-primary);
  letter-spacing: -0.03em;
}
.nav ul {
  display: flex;
  gap: var(--spacing-lg);
}
.nav a {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition);
}
.nav a:hover { color: var(--color-primary); }
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--color-primary);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* =====================================================
   Hero
   ===================================================== */
.hero {
  padding: var(--spacing-2xl) 0;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: #fff;
}
.hero__content {
  max-width: 640px;
}
.hero__title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  line-height: var(--line-height-tight);
  letter-spacing: -0.03em;
  margin-bottom: var(--spacing-md);
}
.hero__lead {
  font-size: var(--font-size-lg);
  opacity: 0.85;
  line-height: var(--line-height-base);
  margin-bottom: var(--spacing-lg);
}

/* =====================================================
   About
   ===================================================== */
.about {
  padding: var(--spacing-2xl) 0;
  background: var(--color-bg);
}
.about__grid {
  display: flex;
  gap: var(--spacing-lg);
  justify-content: center;
  flex-wrap: wrap;
}
.about__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
  min-width: 160px;
}
.about__number {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: var(--color-highlight);
  letter-spacing: -0.02em;
}
.about__label {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  font-weight: 500;
}

/* =====================================================
   Services
   ===================================================== */
.services {
  padding: var(--spacing-2xl) 0;
  background: var(--color-bg-alt);
}
.services__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-md);
}
.service-card {
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
}
.service-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}
.service-card__icon {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: var(--color-highlight);
  margin-bottom: var(--spacing-sm);
  letter-spacing: -0.02em;
}
.service-card__title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
}
.service-card__text {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height-base);
}

/* =====================================================
   Works
   ===================================================== */
.works {
  padding: var(--spacing-2xl) 0;
  background: var(--color-bg);
}
.works__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-md);
}
.work-card {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
}
.work-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}
.work-card__img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}
.work-card__img--placeholder {
  background: linear-gradient(135deg, var(--color-bg-alt) 0%, var(--color-border) 100%);
}
.work-card__body {
  padding: var(--spacing-sm);
}
.work-card__tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-highlight);
  margin-bottom: var(--spacing-xs);
}
.work-card__title {
  font-size: var(--font-size-base);
  font-weight: 600;
}

/* =====================================================
   Contact
   ===================================================== */
.contact {
  padding: var(--spacing-2xl) 0;
  background: var(--color-bg-alt);
}
.contact-form {
  max-width: 600px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}
.form-group label {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text);
}
.required { color: var(--color-highlight); margin-left: 2px; }
.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  color: var(--color-text);
  background: var(--color-bg);
  transition: border-color var(--transition), box-shadow var(--transition);
  outline: none;
  resize: vertical;
}
.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(15, 52, 96, 0.12);
}
.form-group input.error,
.form-group textarea.error {
  border-color: var(--color-highlight);
}
.contact-form .btn { align-self: flex-start; }

/* =====================================================
   Footer
   ===================================================== */
.site-footer {
  background: var(--color-primary);
  color: rgba(255,255,255,0.6);
  padding: var(--spacing-lg) 0;
}
.site-footer .container {
  display: flex;
  align-items: center;
  justify-content: center;
}
.site-footer__copy {
  font-size: var(--font-size-sm);
}

/* =====================================================
   Scroll-in animation
   ===================================================== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* =====================================================
   Responsive — 768px breakpoint
   ===================================================== */
@media (max-width: 768px) {
  :root {
    --font-size-3xl: 36px;
    --font-size-2xl: 28px;
    --font-size-xl:  22px;
    --spacing-2xl:   72px;
  }

  /* Nav */
  .nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md);
  }
  .nav.open { display: block; }
  .nav ul { flex-direction: column; gap: var(--spacing-sm); }
  .nav-toggle { display: flex; }

  /* Grids → single column */
  .services__grid,
  .works__grid { grid-template-columns: 1fr; }

  .about__grid { gap: var(--spacing-md); }

  .hero { padding: var(--spacing-xl) 0; }
  .hero__title { font-size: var(--font-size-2xl); }

  .contact-form .btn { width: 100%; }
}