/* ==========================================================================
   YK Company Corporate Site — Design System
   ========================================================================== */

:root {
  --color-navy-900: #0d1b2e;
  --color-navy-800: #142943;
  --color-navy-700: #1c3a5e;
  --color-navy-600: #2b4d78;
  --color-gold-500: #b8912f;
  --color-gold-400: #cba64a;
  --color-gold-100: #f4ecd8;
  --color-ink: #1f2733;
  --color-body: #4a5568;
  --color-muted: #7c8798;
  --color-line: #e4e7ec;
  --color-bg: #ffffff;
  --color-bg-soft: #f7f8fa;
  --color-bg-navy-tint: #eef2f6;

  --font-serif: "Noto Serif JP", "Yu Mincho", serif;
  --font-sans: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", sans-serif;

  --container-w: 1120px;
  --radius-sm: 4px;
  --radius-md: 10px;
  --radius-lg: 18px;
  --shadow-sm: 0 2px 8px rgba(13, 27, 46, 0.06);
  --shadow-md: 0 12px 32px rgba(13, 27, 46, 0.10);
  --transition: 0.25s ease;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-body);
  background: var(--color-bg);
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  letter-spacing: 0.02em;
}

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

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

ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  color: var(--color-ink);
  margin: 0;
  line-height: 1.5;
  font-weight: 600;
}

p {
  margin: 0;
}

.container {
  width: 100%;
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Section scaffolding ---------- */

.section {
  padding: 96px 0;
}

.section--soft {
  background: var(--color-bg-soft);
}

.section--navy {
  background: var(--color-navy-900);
  color: rgba(255, 255, 255, 0.82);
}

.section--navy h1,
.section--navy h2,
.section--navy h3 {
  color: #fff;
}

.section-head {
  max-width: 640px;
  margin: 0 auto 56px;
  text-align: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 0.78rem;
  letter-spacing: 0.24em;
  color: var(--color-gold-500);
  font-weight: 600;
  margin-bottom: 14px;
}

.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--color-gold-500);
}

.section-head h2 {
  font-size: clamp(1.5rem, 2.4vw, 2rem);
  margin-bottom: 14px;
}

.heading-with-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-top: 20px;
}

.heading-icon {
  flex: none;
  width: 108px;
  height: 108px;
  border-radius: 50%;
  background: var(--color-gold-100);
  color: var(--color-gold-500);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.heading-icon img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.section-head p {
  color: var(--color-muted);
}

.section--navy .section-head p {
  color: rgba(255, 255, 255, 0.65);
}

/* ---------- Header ---------- */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.site-header.is-scrolled {
  border-bottom-color: var(--color-line);
  box-shadow: var(--shadow-sm);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

.brand {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-mark {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-navy-900);
  letter-spacing: 0.04em;
}

.brand-sub {
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  color: var(--color-gold-500);
  margin-top: 2px;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-navy-900);
  transition: transform var(--transition), opacity var(--transition);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 40px;
}

.nav-links {
  display: flex;
  gap: 34px;
}

.nav-links a {
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--color-navy-800);
  position: relative;
  padding: 6px 0;
}

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 1px;
  background: var(--color-gold-500);
  transition: width var(--transition);
}

.nav-links a:hover::after,
.nav-links a.is-active::after {
  width: 100%;
}

.nav-links a.is-active {
  color: var(--color-gold-500);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 30px;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform var(--transition), background var(--transition), color var(--transition), border-color var(--transition);
  white-space: nowrap;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn--primary {
  background: var(--color-navy-900);
  color: #fff;
}

.btn--primary:hover {
  background: var(--color-gold-500);
}

.btn--ghost {
  border-color: rgba(255, 255, 255, 0.5);
  color: #fff;
}

.btn--ghost:hover {
  background: rgba(255, 255, 255, 0.12);
}

.btn--outline {
  border-color: var(--color-navy-900);
  color: var(--color-navy-900);
}

.btn--outline:hover {
  background: var(--color-navy-900);
  color: #fff;
}

.btn--sm {
  padding: 10px 22px;
  font-size: 0.78rem;
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  padding: 200px 0 140px;
  background: linear-gradient(155deg, var(--color-navy-900) 0%, var(--color-navy-700) 62%, var(--color-navy-600) 100%);
  color: #fff;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 82% 18%, rgba(203, 166, 74, 0.22), transparent 42%),
    radial-gradient(circle at 12% 88%, rgba(203, 166, 74, 0.12), transparent 40%);
  pointer-events: none;
}

.hero .container {
  position: relative;
}

.hero-inner {
  max-width: 680px;
}

.hero .eyebrow {
  color: var(--color-gold-400);
}

.hero h1 {
  font-size: clamp(2rem, 4.2vw, 3.1rem);
  color: #fff;
  margin-bottom: 24px;
}

.hero h1 em {
  font-style: normal;
  color: var(--color-gold-400);
}

.hero p.lead {
  font-size: 1.02rem;
  color: rgba(255, 255, 255, 0.72);
  max-width: 540px;
  margin-bottom: 40px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 64px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, auto);
  gap: 40px;
  padding-top: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.16);
}

.hero-stats .stat-num {
  font-family: var(--font-serif);
  font-size: 1.7rem;
  color: #fff;
  display: flex;
  align-items: baseline;
  gap: 2px;
}

.hero-stats .stat-num small {
  font-size: 0.85rem;
  color: var(--color-gold-400);
}

.hero-stats .stat-label {
  font-size: 0.74rem;
  color: rgba(255, 255, 255, 0.56);
  margin-top: 4px;
  letter-spacing: 0.04em;
}

/* ---------- Page header (sub pages) ---------- */

.page-header {
  padding: 172px 0 72px;
  background: linear-gradient(155deg, var(--color-navy-900) 0%, var(--color-navy-700) 100%);
  color: #fff;
}

.page-header .eyebrow {
  color: var(--color-gold-400);
}

.page-header h1 {
  color: #fff;
  font-size: clamp(1.7rem, 3vw, 2.3rem);
}

.breadcrumb {
  margin-top: 18px;
  font-size: 0.78rem;
  color: rgba(255, 255, 255, 0.55);
  display: flex;
  gap: 8px;
}

.breadcrumb a:hover {
  color: var(--color-gold-400);
}

/* ---------- Cards / grids ---------- */

.grid {
  display: grid;
  gap: 28px;
}

.grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

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

.card {
  background: #fff;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  transition: box-shadow var(--transition), transform var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--color-gold-100);
  color: var(--color-gold-500);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
}

.card h3 {
  font-size: 1.08rem;
  margin-bottom: 12px;
}

.card p {
  font-size: 0.9rem;
  color: var(--color-muted);
}

.card .tag {
  display: inline-block;
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--color-gold-500);
  background: var(--color-gold-100);
  padding: 4px 12px;
  border-radius: 999px;
  margin-bottom: 16px;
}

/* ---------- Split / feature rows ---------- */

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.split-media {
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 4 / 3;
  background: linear-gradient(150deg, var(--color-navy-800), var(--color-navy-600));
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.split-media::after {
  content: "";
  position: absolute;
  inset: 18px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: calc(var(--radius-lg) - 6px);
}

.split-media .media-mark {
  font-family: var(--font-serif);
  color: rgba(255, 255, 255, 0.85);
  font-size: 1rem;
  letter-spacing: 0.14em;
}

.split-body h2 {
  font-size: clamp(1.4rem, 2.2vw, 1.9rem);
  margin-bottom: 20px;
}

.split-body p {
  color: var(--color-muted);
  margin-bottom: 16px;
}

.check-list li {
  display: flex;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-line);
  font-size: 0.92rem;
  color: var(--color-body);
}

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

.check-list li::before {
  content: "";
  flex: none;
  width: 18px;
  height: 18px;
  margin-top: 3px;
  border-radius: 50%;
  background: var(--color-gold-500);
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%23000' d='M9 16.2 4.8 12l-1.4 1.4L9 19 21 7l-1.4-1.4z'/%3E%3C/svg%3E") center / 12px no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%23000' d='M9 16.2 4.8 12l-1.4 1.4L9 19 21 7l-1.4-1.4z'/%3E%3C/svg%3E") center / 12px no-repeat;
}

/* ---------- Stats band ---------- */

.stats-band {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.stats-band .stat-num {
  font-family: var(--font-serif);
  font-size: 2.2rem;
  color: var(--color-gold-400);
}

.stats-band .stat-label {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.6);
  margin-top: 8px;
}

/* ---------- Table (company overview) ---------- */

.info-table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.info-table tr {
  border-bottom: 1px solid var(--color-line);
}

.info-table tr:last-child {
  border-bottom: none;
}

.info-table th,
.info-table td {
  text-align: left;
  padding: 20px 32px;
  font-size: 0.92rem;
  vertical-align: top;
}

.info-table th {
  width: 220px;
  color: var(--color-navy-800);
  background: var(--color-bg-soft);
  font-weight: 600;
  font-family: var(--font-serif);
}

.info-table td {
  color: var(--color-body);
}

.placeholder-note {
  color: var(--color-gold-500);
  font-size: 0.78rem;
}

/* ---------- Timeline ---------- */

.flow-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  counter-reset: step;
}

.flow-step {
  position: relative;
  padding: 32px 24px 24px;
  background: #fff;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
}

.flow-step::before {
  counter-increment: step;
  content: counter(step, decimal-leading-zero);
  font-family: var(--font-serif);
  font-size: 1.6rem;
  color: var(--color-gold-500);
  display: block;
  margin-bottom: 16px;
}

.flow-step h4 {
  font-size: 0.98rem;
  margin-bottom: 10px;
}

.flow-step p {
  font-size: 0.85rem;
  color: var(--color-muted);
}

/* ---------- CTA band ---------- */

.cta-band {
  background: linear-gradient(150deg, var(--color-navy-900), var(--color-navy-700));
  border-radius: var(--radius-lg);
  padding: 64px;
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}

.cta-band h2 {
  color: #fff;
  font-size: clamp(1.3rem, 2vw, 1.7rem);
  margin-bottom: 10px;
}

.cta-band .eyebrow {
  margin-bottom: 12px;
}

.cta-band-heading {
  font-family: var(--font-sans);
  font-weight: 700;
}

.cta-band-text {
  margin-top: 12px;
  max-width: 480px;
}

.cta-contact-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

.cta-contact-badge {
  display: inline-flex;
  align-items: center;
  padding: 12px 20px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.6);
  background: #fff;
  color: var(--color-navy-800);
  font-size: 0.88rem;
  font-weight: 600;
  box-shadow: 0 10px 24px rgba(13, 27, 46, 0.28);
  transition: transform var(--transition), box-shadow var(--transition);
}

.cta-contact-badge:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 30px rgba(13, 27, 46, 0.36);
}

.cta-band p {
  color: rgba(255, 255, 255, 0.68);
}

/* ---------- Forms ---------- */

.form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-field.full {
  grid-column: 1 / -1;
}

.form-field label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-navy-800);
}

.form-field .required {
  color: #b3413d;
  font-size: 0.7rem;
  margin-left: 6px;
}

.form-field input,
.form-field select,
.form-field textarea {
  font: inherit;
  padding: 13px 16px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: #fff;
  color: var(--color-ink);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--color-gold-500);
  box-shadow: 0 0 0 3px rgba(184, 145, 47, 0.14);
}

.form-field textarea {
  resize: vertical;
  min-height: 140px;
}

.form-consent {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.82rem;
  color: var(--color-muted);
}

.form-consent input {
  margin-top: 4px;
}

.form-note {
  font-size: 0.8rem;
  color: var(--color-muted);
}

.form-status {
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  display: none;
}

.form-status.is-visible {
  display: block;
}

.form-status--success {
  background: #eaf5ee;
  color: #276a43;
}

.form-status--error {
  background: #fbeceb;
  color: #a5342e;
}

/* ---------- Contact info cards ---------- */

.contact-meta {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 56px;
}

.contact-meta .card {
  padding: 28px 26px;
}

.contact-meta h3 {
  font-size: 0.95rem;
}

.contact-meta p {
  font-size: 0.88rem;
}

/* ---------- Footer ---------- */

.site-footer {
  background: var(--color-navy-900);
  color: rgba(255, 255, 255, 0.6);
  padding: 72px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand .brand-mark {
  color: #fff;
}

.footer-brand p {
  margin-top: 16px;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
  max-width: 280px;
}

.footer-col h4 {
  color: #fff;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  margin-bottom: 18px;
}

.footer-col li {
  margin-bottom: 12px;
  font-size: 0.85rem;
}

.footer-col a:hover {
  color: var(--color-gold-400);
}

.footer-bottom {
  padding-top: 28px;
  display: flex;
  justify-content: space-between;
  font-size: 0.76rem;
  color: rgba(255, 255, 255, 0.4);
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- Utilities ---------- */

.mt-lg { margin-top: 56px; }
.text-center { text-align: center; }

/* ---------- Responsive ---------- */

@media (max-width: 960px) {
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
  .split { grid-template-columns: 1fr; gap: 40px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-band { grid-template-columns: repeat(2, 1fr); gap: 32px; }
  .flow-steps { grid-template-columns: repeat(2, 1fr); }
  .form-grid { grid-template-columns: 1fr; }
  .contact-meta { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .nav-toggle { display: flex; }

  .main-nav {
    position: fixed;
    top: 76px;
    left: 0;
    right: 0;
    bottom: 0;
    background: #fff;
    flex-direction: column;
    align-items: flex-start;
    padding: 32px 24px;
    gap: 28px;
    transform: translateX(100%);
    transition: transform var(--transition);
    overflow-y: auto;
  }

  .main-nav.is-open {
    transform: translateX(0);
  }

  .nav-links {
    flex-direction: column;
    gap: 20px;
    width: 100%;
  }

  .nav-links a {
    display: block;
    font-size: 1rem;
  }

  .hero { padding: 152px 0 96px; }
  .hero-stats { grid-template-columns: 1fr; gap: 20px; }
  .page-header { padding: 140px 0 56px; }
  .grid--3 { grid-template-columns: 1fr; }
  .grid--2 { grid-template-columns: 1fr; }
  .section { padding: 64px 0; }
  .cta-band { flex-direction: column; align-items: flex-start; padding: 40px 28px; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .footer-bottom { flex-direction: column; }
  .stats-band { grid-template-columns: 1fr 1fr; }
  .flow-steps { grid-template-columns: 1fr; }
}

/* ---------- Dark mode (respect system preference) ---------- */

@media (prefers-color-scheme: dark) {
  body {
    background: #0b1420;
    color: #c6cdd8;
  }

  .site-header {
    background: rgba(11, 20, 32, 0.92);
  }

  .site-header.is-scrolled {
    border-bottom-color: rgba(255, 255, 255, 0.08);
  }

  .brand-mark { color: #fff; }
  .nav-links a { color: rgba(255, 255, 255, 0.82); }
  .nav-toggle span { background: #fff; }

  h1, h2, h3, h4 { color: #f2f4f7; }

  .section--soft { background: #101c2c; }

  .card {
    background: #101c2c;
    border-color: rgba(255, 255, 255, 0.08);
  }

  .info-table {
    background: #101c2c;
  }

  .info-table th {
    background: #0d1826;
    color: #f2f4f7;
  }

  .info-table tr { border-bottom-color: rgba(255, 255, 255, 0.08); }

  .flow-step {
    background: #101c2c;
    border-color: rgba(255, 255, 255, 0.08);
  }

  .form-field input,
  .form-field select,
  .form-field textarea {
    background: #101c2c;
    border-color: rgba(255, 255, 255, 0.14);
    color: #f2f4f7;
  }

  .btn--outline { border-color: rgba(255, 255, 255, 0.5); color: #fff; }
  .btn--outline:hover { background: rgba(255, 255, 255, 0.1); color: #fff; }
  .btn--primary { background: var(--color-gold-500); color: #0b1420; }
  .btn--primary:hover { background: var(--color-gold-400); }
}