/* =========================================================
   Tokens / Reset
========================================================== */

:root {
  --navy: #5b263c;
  --navy-soft: #8c3a5c;
  --text: #202934;
  --muted: #6d7680;
  --line: #dce2e8;
  --bg: #f5f7f9;
  --white: #ffffff;
  --gold: #b79a63;
  --accent: #3f1a29;
  --ink: #081d35;
  --ink-soft: #163654;
  --max-width: 1180px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Hiragino Sans",
    "Yu Gothic",
    "Yu Gothic UI",
    "Noto Sans JP",
    sans-serif;

  color: var(--text);
  background: var(--white);
  line-height: 1.9;
  letter-spacing: 0.035em;
}

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

::selection {
  color: var(--white);
  background: var(--accent);
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}


/* =========================================================
   Header / Nav
========================================================== */

header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1000;

  width: 100%;
  height: 76px;

  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);

  border-bottom: 1px solid rgba(220, 226, 232, 0.85);
}

.header-inner {
  max-width: var(--max-width);
  height: 100%;
  margin: 0 auto;
  padding: 0 28px;

  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  color: var(--navy);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: 0.09em;
}

.logo span {
  color: var(--gold);
}

nav {
  display: flex;
  align-items: center;
  gap: 32px;

  color: var(--navy);
  font-size: 13px;
  letter-spacing: 0.08em;
}

nav a {
  opacity: 0.78;
  transition:
    opacity 0.2s ease,
    color 0.2s ease;
}

nav a:hover {
  opacity: 1;
  color: var(--accent);
}


/* =========================================================
   Mobile nav
========================================================== */

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;

  width: 32px;
  height: 32px;

  background: transparent;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;

  background: var(--navy);

  transition:
    transform 0.25s ease,
    opacity 0.25s ease;
}

.nav-toggle.is-active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.is-active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.is-active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.mobile-nav {
  position: fixed;
  top: 76px;
  left: 0;
  right: 0;
  z-index: 999;

  max-height: 0;
  overflow: hidden;

  background: var(--white);
  border-bottom: 1px solid var(--line);

  transition: max-height 0.3s ease;
}

.mobile-nav.is-open {
  max-height: 420px;
}

.mobile-nav-inner {
  display: flex;
  flex-direction: column;

  padding: 8px 28px 24px;
}

.mobile-nav a {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);

  color: var(--navy);
  font-size: 15px;
  letter-spacing: 0.06em;

  transition: color 0.2s ease;
}

.mobile-nav a:last-child {
  border-bottom: none;
}

.mobile-nav a:hover,
.mobile-nav a:focus-visible {
  color: var(--accent);
}

.eyebrow {
  position: relative;

  display: inline-block;
  margin-bottom: 28px;
  padding-left: 54px;

  color: var(--navy-soft);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";

  position: absolute;
  top: 50%;
  left: 0;

  width: 38px;
  height: 1px;

  background: var(--gold);
}


/* =========================================================
   Page hero (About / Projects / Journal)
========================================================== */

.page-hero {
  padding: 170px 28px 110px;

  background:
    linear-gradient(
      135deg,
      #ffffff 0%,
      #ffffff 58%,
      #f5f7f9 100%
    );
}

.page-hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.breadcrumb {
  margin-bottom: 38px;

  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.breadcrumb a {
  color: var(--navy-soft);
}

.page-hero h1 {
  max-width: 950px;

  color: var(--navy);
  font-size: clamp(42px, 6vw, 68px);
  font-weight: 500;
  line-height: 1.45;
  letter-spacing: 0.04em;
}

.page-hero .hero-lead {
  max-width: 800px;
  margin-top: 38px;

  color: #485565;
  font-size: 17px;
  line-height: 2.1;
}


/* =========================================================
   Section grid (shared by all pages)
========================================================== */

section {
  padding: 110px 28px;
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-heading {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 70px;

  margin-bottom: 62px;
}

.section-label {
  padding-top: 16px;
  border-top: 1px solid var(--gold);

  color: var(--gold);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.section-heading h2 {
  max-width: 780px;

  color: var(--navy);
  font-size: clamp(30px, 4vw, 46px);
  font-weight: 500;
  line-height: 1.55;
}


/* =========================================================
   Buttons
========================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;

  min-width: 180px;
  height: 52px;
  padding: 0 28px;

  border: 1px solid var(--navy);

  color: var(--navy);
  background: transparent;

  font-size: 13px;
  letter-spacing: 0.09em;

  transition:
    background 0.2s ease,
    color 0.2s ease,
    border-color 0.2s ease;
}

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

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

.btn.secondary {
  color: var(--navy);
  background: transparent;
}

.btn.secondary:hover {
  color: var(--white);
  background: var(--ink);
}

.not-found-links .btn {
  min-width: 0;
}


/* =========================================================
   Contact
========================================================== */

.contact {
  padding-top: 130px;
  padding-bottom: 130px;

  color: var(--white);
  background: var(--ink);
}

.contact-inner {
  max-width: 900px;
  margin: 0 auto;

  text-align: center;
}

.contact-small {
  display: block;

  margin-bottom: 24px;

  color: var(--gold);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.contact h2 {
  margin-bottom: 26px;

  font-size: clamp(32px, 5vw, 52px);
  font-weight: 500;
  line-height: 1.45;
}

.contact p {
  max-width: 640px;
  margin: 0 auto 42px;

  color: rgba(255, 255, 255, 0.72);
  font-size: 15px;
}

.contact .btn {
  color: var(--navy);
  background: var(--white);
  border-color: var(--white);
}

.contact .btn:hover {
  color: var(--white);
  background: transparent;
}


/* =========================================================
   Footer
========================================================== */

footer {
  padding: 38px 28px;

  color: rgba(255, 255, 255, 0.62);
  background: #061426;

  font-size: 12px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;

  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.footer-logo {
  color: var(--white);
  font-size: 17px;
  letter-spacing: 0.08em;
}

.footer-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.footer-nav a {
  color: rgba(255, 255, 255, 0.72);
  transition: color 0.2s ease;
}

.footer-nav a:hover {
  color: var(--white);
}


/* =========================================================
   Back to top
========================================================== */

.back-to-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 900;

  display: flex;
  align-items: center;
  justify-content: center;

  width: 40px;
  height: 40px;

  color: var(--white);
  background: var(--ink);
  border: none;
  border-radius: 50%;

  font-size: 16px;
  cursor: pointer;

  opacity: 0;
  transform: translateY(8px);
  pointer-events: none;

  transition:
    opacity 0.2s ease,
    transform 0.2s ease,
    background 0.2s ease;
}

.back-to-top.is-visible {
  opacity: 0.85;
  transform: translateY(0);
  pointer-events: auto;
}

.back-to-top:hover,
.back-to-top:focus-visible {
  opacity: 1;
  background: var(--ink-soft);
}


/* =========================================================
   Responsive
========================================================== */

@media (max-width: 900px) {
  .header-inner > nav {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .page-hero {
    padding-top: 140px;
    padding-bottom: 80px;
  }

  section {
    padding: 84px 22px;
  }

  .section-heading {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

@media (max-width: 560px) {
  .header-inner {
    padding: 0 20px;
  }

  .page-hero {
    padding-left: 20px;
    padding-right: 20px;
  }

  .page-hero h1 {
    font-size: 38px;
  }

  .page-hero .hero-lead br {
    display: none;
  }

  .btn {
    width: 100%;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .footer-nav {
    gap: 16px;
  }
}