/* =============================================
   NOS Corporate Site — Main Stylesheet
   Design: Minimal, Refined, Royal Blue + White + Gray
   Brand Color: #4169E1
   ============================================= */

/* ---- CSS Variables ---- */
:root {
  --color-primary:    #2a3f8f;
  --color-primary-dk: #1a2a6b;
  --color-accent:     #4169E1;
  --color-accent-lt:  #6384e8;
  --color-white:      #ffffff;
  --color-off-white:  #f7f8fa;
  --color-gray-50:    #f3f4f6;
  --color-gray-100:   #e8eaee;
  --color-gray-200:   #d1d5db;
  --color-gray-400:   #9ca3af;
  --color-gray-600:   #6b7280;
  --color-gray-800:   #374151;
  --color-gray-900:   #1f2937;
  --color-text:       #1f2937;
  --color-text-sub:   #6b7280;

  --font-sans:    'Noto Sans JP', 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', 'Yu Gothic', 'Meiryo', sans-serif;
  --font-display: 'Noto Serif JP', 'Hiragino Mincho ProN', 'Yu Mincho', serif;
  --font-en:      'Inter', sans-serif;

  --space-xs:  0.5rem;
  --space-sm:  1rem;
  --space-md:  2rem;
  --space-lg:  4rem;
  --space-xl:  7rem;
  --space-2xl: 10rem;

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

  --shadow-card: 0 2px 24px rgba(26,58,92,0.07);
  --shadow-hover: 0 8px 40px rgba(26,58,92,0.13);

  --transition: 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --transition-fast: 0.2s ease;

  --header-h: 72px;
  --container: 1140px;
}

/* ---- Reset ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-white);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }

/* ---- Container ---- */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(1.5rem, 5vw, 4rem);
}

/* ---- Section base ---- */
.section { padding: var(--space-xl) 0; }
.section--gray { background: var(--color-off-white); }

.section-label {
  font-family: var(--font-en);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.25em;
  color: var(--color-accent);
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.section-label--light { color: rgba(255,255,255,0.7); }

.section-header {
  margin-bottom: var(--space-lg);
}
.section-title {
  font-family: var(--font-sans);
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  font-weight: 300;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  line-height: 1.3;
}
.section-desc {
  margin-top: 1rem;
  color: var(--color-text-sub);
  font-size: 0.95rem;
  font-weight: 300;
}

/* =============================================
   HEADER
   ============================================= */
.site-header,
.site-header.scrolled {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: #ffffff !important;
  border-bottom: 1px solid var(--color-gray-100) !important;
  backdrop-filter: none !important;
  transition: none !important;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

/* Logo */
.site-logo {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
}
.logo-mark {
  font-family: var(--font-en);
  font-size: 1.5rem;
  font-weight: 300;
  letter-spacing: 0.15em;
  color: var(--color-primary);
}
.logo-sub {
  font-size: 0.7rem;
  font-weight: 400;
  letter-spacing: 0.12em;
  color: var(--color-gray-600);
}

/* Nav */
.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(1.5rem, 3vw, 3rem);
}
.nav-link {
  font-size: 0.82rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--color-gray-800);
  transition: color var(--transition-fast);
  position: relative;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-accent);
  transition: width var(--transition-fast);
}
.nav-link:hover { color: var(--color-accent); }
.nav-link:hover::after { width: 100%; }
.nav-link--contact {
  padding: 0.5rem 1.4rem;
  border: 1px solid var(--color-primary);
  border-radius: 2px;
  color: var(--color-primary);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  transition: background var(--transition-fast), color var(--transition-fast);
}
.nav-link--contact::after { display: none; }
.nav-link--contact:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 24px;
  height: 1px;
  background: var(--color-primary);
  transition: transform 0.3s, opacity 0.3s;
}
.hamburger.active span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* =============================================
   FIRST VIEW
   ============================================= */
.fv {
  min-height: 75vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  background: var(--color-primary-dk);
}

.fv-bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  /* 背景画像はfront-page.phpのインラインスタイルで指定 */
  background: transparent;
}
.fv-bg::before,
.fv-bg::after {
  display: none;
}
.fv-grid-overlay {
  display: none;
}

.fv-content {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  padding-top: var(--header-h);
  width: 100%;
}

.fv-text {
  width: 100%;
  max-width: 560px;
  background: rgba(0, 0, 0, 0.50);
  backdrop-filter: blur(4px);
  padding: 3.5rem 4rem;
  border-radius: 4px;
}

.fv-eyebrow {
  font-family: var(--font-en);
  font-size: 0.72rem;
  font-weight: 300;
  letter-spacing: 0.3em;
  color: rgba(255,255,255,0.5);
  text-transform: uppercase;
  margin-bottom: 1.5rem;
}

.fv-headline {
  font-family: var(--font-sans);
  font-size: 2.8rem;
  font-weight: 300;
  line-height: 1.5;
  letter-spacing: 0.06em;
  color: var(--color-white);
  margin-bottom: 1.8rem;
  white-space: nowrap;
}

.fv-sub {
  font-size: 0.9rem;
  font-weight: 300;
  line-height: 2;
  color: rgba(255,255,255,0.65);
  margin-bottom: 3rem;
  letter-spacing: 0.05em;
}

.fv-actions {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

/* Geometric visual */
.fv-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}
.fv-figure {
  position: relative;
  width: 360px;
  height: 360px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.fig-ring {
  position: absolute;
  border-radius: 50%;
  border: 1px solid rgba(59,130,212,0.2);
  animation: ring-spin linear infinite;
}
.fig-ring--1 { width: 100%; height: 100%; animation-duration: 40s; }
.fig-ring--2 { width: 72%; height: 72%; border-color: rgba(59,130,212,0.3); animation-duration: 28s; animation-direction: reverse; }
.fig-ring--3 { width: 44%; height: 44%; border-color: rgba(59,130,212,0.45); animation-duration: 18s; }
@keyframes ring-spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}
.fig-core {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: rgba(37,99,171,0.3);
  border: 1px solid rgba(59,130,212,0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-en);
  font-size: 2rem;
  font-weight: 300;
  letter-spacing: 0.1em;
  color: rgba(255,255,255,0.9);
}

/* Scroll indicator */
.fv-scroll-indicator {
  position: absolute;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: rgba(255,255,255,0.35);
}
.fv-scroll-indicator span {
  font-family: var(--font-en);
  font-size: 0.6rem;
  letter-spacing: 0.3em;
  text-transform: uppercase;
}
.scroll-line {
  width: 1px;
  height: 50px;
  background: linear-gradient(to bottom, rgba(255,255,255,0), rgba(255,255,255,0.4));
  animation: scroll-drop 1.8s ease-in-out infinite;
}
@keyframes scroll-drop {
  0%, 100% { opacity: 0.2; transform: scaleY(0.5); transform-origin: top; }
  50% { opacity: 1; transform: scaleY(1); }
}

/* =============================================
   BUTTONS
   ============================================= */
.btn {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  padding: 0.9rem 2.2rem;
  border-radius: 2px;
  transition: all var(--transition-fast);
  cursor: pointer;
  border: 1px solid transparent;
}
.btn--primary {
  background: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
}
.btn--primary:hover {
  background: var(--color-accent-lt);
  border-color: var(--color-accent-lt);
  transform: translateY(-1px);
}
.btn--ghost {
  background: transparent;
  color: rgba(255,255,255,0.8);
  border-color: rgba(255,255,255,0.3);
}
.btn--ghost:hover {
  background: rgba(255,255,255,0.08);
  border-color: rgba(255,255,255,0.6);
}
.btn--white {
  background: var(--color-white);
  color: var(--color-primary);
  border-color: var(--color-white);
}
.btn--white:hover {
  background: transparent;
  color: var(--color-white);
  border-color: var(--color-white);
}

/* Text link */
.text-link {
  font-size: 0.85rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: gap var(--transition-fast);
}
.text-link:hover { gap: 0.8rem; }
.text-link .arrow { transition: transform var(--transition-fast); }
.text-link:hover .arrow { transform: translateX(4px); }

/* =============================================
   ABOUT
   ============================================= */
.about-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 6vw, 6rem);
  align-items: center;
}
.about-lead {
  font-size: clamp(1.1rem, 2vw, 1.5rem);
  font-weight: 300;
  line-height: 1.7;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  margin-bottom: 1.5rem;
}
.about-desc {
  font-size: 0.9rem;
  font-weight: 300;
  line-height: 2;
  color: var(--color-text-sub);
  margin-bottom: 2rem;
}
.about-numbers {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
  padding-left: clamp(1.5rem, 4vw, 3rem);
  border-left: 1px solid var(--color-gray-200);
}
.num-item {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.num-value {
  font-family: var(--font-en);
  font-size: clamp(2.4rem, 4vw, 3.6rem);
  font-weight: 300;
  color: var(--color-primary);
  line-height: 1;
  letter-spacing: -0.02em;
}
.num-value small {
  font-size: 0.4em;
  font-family: var(--font-sans);
  font-weight: 300;
  letter-spacing: 0;
}
.num-label {
  font-size: 0.75rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--color-gray-400);
}

/* =============================================
   SERVICE
   ============================================= */
.service-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}
.service-card {
  background: var(--color-white);
  border: 1px solid var(--color-gray-100);
  border-radius: var(--radius-md);
  padding: 2.5rem 2rem;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  position: relative;
  overflow: hidden;
}
.service-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent) 0%, var(--color-accent-lt) 100%);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition);
}
.service-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--color-gray-200);
}
.service-card:hover::before { transform: scaleX(1); }

.service-card__icon {
  width: 52px;
  height: 52px;
  color: var(--color-accent);
  margin-bottom: 1.5rem;
}
.service-card__icon svg { width: 100%; height: 100%; }

.service-card__num {
  font-family: var(--font-en);
  font-size: 0.65rem;
  font-weight: 400;
  letter-spacing: 0.2em;
  color: var(--color-gray-400);
  margin-bottom: 0.75rem;
}
.service-card__title {
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  line-height: 1.5;
  margin-bottom: 1rem;
}
.service-card__desc {
  font-size: 0.85rem;
  font-weight: 300;
  line-height: 1.9;
  color: var(--color-text-sub);
  margin-bottom: 1.5rem;
}
.service-card__link {
  font-family: var(--font-en);
  font-size: 0.78rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  transition: gap var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.service-card__link:hover { gap: 0.7rem; }

/* =============================================
   LINK PANELS
   ============================================= */
.panels-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}
.panel-card {
  display: block;
  border-radius: var(--radius-md);
  overflow: hidden;
  position: relative;
  min-height: 280px;
  transition: transform var(--transition), box-shadow var(--transition);
}
.panel-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}
.panel-card--company {
  background: linear-gradient(135deg, var(--color-primary) 0%, #1e4a78 100%);
}
.panel-card--recruit {
  background: linear-gradient(135deg, #2c3e50 0%, #3d566e 100%);
}
.panel-card__inner {
  padding: 3rem;
  color: var(--color-white);
  height: 100%;
  display: flex;
  flex-direction: column;
  position: relative;
}
.panel-card__label {
  font-family: var(--font-en);
  font-size: 0.65rem;
  font-weight: 400;
  letter-spacing: 0.3em;
  color: rgba(255,255,255,0.5);
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.panel-card__title {
  font-size: 1.8rem;
  font-weight: 300;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
}
.panel-card__desc {
  font-size: 0.85rem;
  font-weight: 300;
  line-height: 1.8;
  color: rgba(255,255,255,0.7);
  flex: 1;
}
.panel-card__arrow {
  display: inline-block;
  margin-top: 2rem;
  font-size: 1.5rem;
  font-weight: 200;
  color: rgba(255,255,255,0.5);
  transition: transform var(--transition-fast), color var(--transition-fast);
}
.panel-card:hover .panel-card__arrow {
  transform: translateX(8px);
  color: rgba(255,255,255,0.9);
}

/* =============================================
   CONTACT CTA
   ============================================= */
.contact-cta {
  position: relative;
  background: var(--color-primary-dk);
  padding: var(--space-xl) 0;
  overflow: hidden;
}
.contact-cta__bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 80% at 20% 50%, rgba(37,99,171,0.2) 0%, transparent 60%),
    radial-gradient(ellipse 40% 60% at 80% 50%, rgba(37,99,171,0.1) 0%, transparent 60%);
}
.contact-cta__inner {
  position: relative;
  z-index: 1;
  text-align: center;
}
.contact-cta__title {
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 300;
  letter-spacing: 0.1em;
  color: var(--color-white);
  margin-bottom: 1.2rem;
}
.contact-cta__desc {
  font-size: 0.9rem;
  font-weight: 300;
  line-height: 2;
  color: rgba(255,255,255,0.6);
  margin-bottom: 3rem;
  letter-spacing: 0.05em;
}
.contact-cta__actions {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}
.contact-tel {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  font-family: var(--font-en);
  font-size: 1.5rem;
  font-weight: 300;
  letter-spacing: 0.08em;
  color: rgba(255,255,255,0.8);
  transition: color var(--transition-fast);
}
.contact-tel:hover { color: var(--color-white); }
.tel-icon {
  display: flex;
  align-items: center;
  color: rgba(255,255,255,0.5);
}
.contact-tel small {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 300;
  color: rgba(255,255,255,0.4);
  letter-spacing: 0.05em;
}

/* =============================================
   FOOTER
   ============================================= */
.site-footer {
  background: var(--color-gray-900);
  padding: 4rem 0 2rem;
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 3rem;
  margin-bottom: 3rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.footer-logo .logo-mark {
  color: rgba(255,255,255,0.9);
  font-size: 1.4rem;
}
.footer-tagline {
  margin-top: 0.75rem;
  font-size: 0.78rem;
  font-weight: 300;
  color: rgba(255,255,255,0.3);
  letter-spacing: 0.1em;
}
.footer-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 2.5rem;
}
.footer-nav a {
  font-size: 0.8rem;
  font-weight: 300;
  letter-spacing: 0.06em;
  color: rgba(255,255,255,0.5);
  transition: color var(--transition-fast);
}
.footer-nav a:hover { color: rgba(255,255,255,0.9); }
.footer-bottom {
  text-align: center;
}
.footer-bottom small {
  font-family: var(--font-en);
  font-size: 0.7rem;
  font-weight: 300;
  letter-spacing: 0.15em;
  color: rgba(255,255,255,0.2);
}

/* =============================================
   ANIMATIONS
   ============================================= */
.fade-up {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94),
              transform 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}
.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}
.fade-up--delay  { transition-delay: 0.15s; }
.fade-up--delay-2 { transition-delay: 0.3s; }

/* =============================================
   RESPONSIVE
   ============================================= */
.sp-only { display: none; }

@media (max-width: 1024px) {
  .fv-headline { white-space: normal; font-size: 2.2rem; }
  .fv-text { max-width: 100%; padding: 2.5rem 2rem; }
  .service-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  :root { --space-xl: 4rem; }

  .sp-only { display: inline; }

  /* Header */
  .hamburger { display: flex; }
  .global-nav {
    position: fixed;
    inset: 0;
    top: var(--header-h);
    background: rgba(14,35,64,0.97);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.4s;
  }
  .global-nav.open {
    opacity: 1;
    pointer-events: auto;
  }
  .nav-list {
    flex-direction: column;
    gap: 2.5rem;
    text-align: center;
  }
  .nav-link {
    color: rgba(255,255,255,0.8);
    font-size: 1rem;
  }
  .nav-link--contact {
    border-color: rgba(255,255,255,0.4);
    color: rgba(255,255,255,0.8);
  }

  /* FV */
  .fv-headline { font-size: 2rem; }
  .fv-actions { flex-direction: column; align-items: center; }

  /* About */
  .about-body {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  .about-numbers {
    padding-left: 0;
    border-left: none;
    border-top: 1px solid var(--color-gray-200);
    padding-top: 2rem;
    flex-direction: row;
    justify-content: space-around;
  }
  .num-item { text-align: center; }

  /* Service */
  .service-grid { grid-template-columns: 1fr; }

  /* Panels */
  .panels-grid { grid-template-columns: 1fr; }

  /* Footer */
  .footer-inner {
    flex-direction: column;
    gap: 2rem;
  }
  .footer-nav ul { gap: 0.5rem 1.5rem; }
}

@media (max-width: 480px) {
  .fv-headline { font-size: 1.7rem; }
  .about-numbers { flex-direction: column; align-items: flex-start; }
  .num-item { align-items: flex-start; }
  .contact-tel { font-size: 1.2rem; }
}

/* =============================================
   UTILITY
   ============================================= */
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}