/* ============================================================
   G-UNION Portfolio — style.css
   ============================================================ */

/* ------------------------------------------------------------
   0. Google Fonts import
   ------------------------------------------------------------ */
@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+JP:wght@400;600;700;900&family=Zen+Kaku+Gothic+New:wght@400;500;700;900&display=swap');

/* ------------------------------------------------------------
   1. CSS Custom Properties
   ------------------------------------------------------------ */
:root {
  /* Colors */
  --color-bg:           #141416;
  --color-bg-warm:      #1a1a1e;
  --color-bg-card:      #18181c;
  --color-accent:       #c8442a;
  --color-accent-light: #e05a3e;
  --color-gold:         #b8a472;
  --color-text:         #e8e6e1;
  --color-text-muted:   #9a9890;
  --color-border:       #2a2a32;

  /* Typography */
  --font-serif:  'Noto Serif JP', 'Georgia', serif;
  --font-sans:   'Zen Kaku Gothic New', 'Hiragino Kaku Gothic ProN', sans-serif;

  /* Spacing scale */
  --sp-1:  4px;
  --sp-2:  8px;
  --sp-3:  12px;
  --sp-4:  16px;
  --sp-5:  24px;
  --sp-6:  32px;
  --sp-7:  48px;
  --sp-8:  64px;
  --sp-9:  96px;
  --sp-10: 128px;

  /* Layout */
  --max-width:      1200px;
  --header-height:  72px;
  --content-pad:    clamp(20px, 5vw, 60px);

  /* Transitions */
  --ease-out:    cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in-out: cubic-bezier(0.45, 0, 0.55, 1);
  --dur-fast:    160ms;
  --dur-base:    280ms;
  --dur-slow:    480ms;

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;

  /* Shadows */
  --shadow-card: 0 2px 24px rgba(0, 0, 0, 0.45);
  --shadow-glow: 0 0 24px rgba(200, 68, 42, 0.18);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  overflow-x: hidden;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.75;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

input, textarea, select {
  font-family: inherit;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: 0.02em;
}

/* ------------------------------------------------------------
   3. Layout Utilities
   ------------------------------------------------------------ */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--content-pad);
}

.section {
  padding-block: var(--sp-10);
}

.section--sm {
  padding-block: var(--sp-8);
}

/* flex helpers */
.flex        { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between{ display: flex; align-items: center; justify-content: space-between; }

/* grid helpers */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--sp-6); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--sp-6); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-5); }

/* text utilities */
.text-center  { text-align: center; }
.text-muted   { color: var(--color-text-muted); }
.text-accent  { color: var(--color-accent); }
.text-gold    { color: var(--color-gold); }
.text-serif   { font-family: var(--font-serif); }

/* ------------------------------------------------------------
   4. Typography Scale
   ------------------------------------------------------------ */
.heading-xl {
  font-family: var(--font-serif);
  font-size: clamp(2.4rem, 6vw, 5rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.01em;
}

.heading-lg {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 700;
}

.heading-md {
  font-family: var(--font-serif);
  font-size: clamp(1.3rem, 2.5vw, 2rem);
  font-weight: 700;
}

.heading-sm {
  font-family: var(--font-serif);
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  font-weight: 600;
}

.body-lg {
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.8;
}

.label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

/* ------------------------------------------------------------
   5. Section Heading Component
   ------------------------------------------------------------ */
.section-heading {
  text-align: center;
  margin-bottom: var(--sp-8);
}

.section-heading__label {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--sp-3);
}

.section-heading__title {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--sp-4);
}

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

.section-heading__desc {
  font-size: clamp(0.8rem, 1.3vw, 0.95rem);
  color: var(--color-text-muted);
  width: max-content;
  max-width: 100%;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.85;
}

.section-heading__line {
  display: block;
  width: 48px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold));
  margin: var(--sp-5) auto 0;
  border-radius: 2px;
}

/* ------------------------------------------------------------
   6. Header
   ------------------------------------------------------------ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  display: flex;
  align-items: center;
  transition: background-color var(--dur-base) var(--ease-out),
              backdrop-filter var(--dur-base) var(--ease-out),
              box-shadow var(--dur-base) var(--ease-out);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--content-pad);
}

/* Scrolled state (added via JS when scrollY >= 60) */
.header.is-scrolled {
  background-color: rgba(12, 12, 14, 0.82);
  backdrop-filter: blur(12px) saturate(1.4);
  -webkit-backdrop-filter: blur(12px) saturate(1.4);
  box-shadow: 0 1px 0 var(--color-border);
}

/* Logo */
.header__logo {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-family: var(--font-serif);
  font-size: 0.8125rem;
  font-weight: 900;
  color: var(--color-text);
  letter-spacing: 0.25em;
  text-decoration: none;
  transition: opacity var(--dur-fast);
}

.header__logo:hover {
  opacity: 0.8;
}

.header__logo-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: 1.5px solid var(--color-accent);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 900;
  color: var(--color-accent);
  letter-spacing: 0;
}

/* Nav */
.header__nav {
  display: flex;
  align-items: center;
  gap: var(--sp-6);
}

.header__nav-link {
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--dur-fast);
  position: relative;
  padding-bottom: 2px;
}

.header__nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--color-accent);
  transition: width var(--dur-base) var(--ease-out);
}

.header__nav-link:hover {
  color: var(--color-text);
}

.header__nav-link:hover::after,
.header__nav-link.is-active::after {
  width: 100%;
}

.header__nav-link.is-active {
  color: var(--color-text);
}

/* CTA button in header */
.header__cta {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 9px 22px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--color-text);
  border: 1.5px solid var(--color-accent);
  border-radius: var(--radius-sm);
  transition: background-color var(--dur-fast), color var(--dur-fast);
}

.header__cta:hover {
  background-color: var(--color-accent);
  color: #fff;
}

/* ------------------------------------------------------------
   7. Hamburger Menu
   ------------------------------------------------------------ */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  gap: 6px;
  cursor: pointer;
  z-index: 1100;
  background: none;
  border: none;
  padding: 0;
  position: relative;
}

.hamburger__line {
  display: block;
  width: 24px;
  height: 1.5px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: transform var(--dur-base) var(--ease-out),
              opacity var(--dur-base) var(--ease-out),
              width var(--dur-base) var(--ease-out);
  transform-origin: center;
}

/* Open state */
.hamburger.is-open .hamburger__line:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

.hamburger.is-open .hamburger__line:nth-child(2) {
  opacity: 0;
  width: 0;
}

.hamburger.is-open .hamburger__line:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* Mobile nav drawer */
.nav-drawer {
  display: none;
  position: fixed;
  top: 0;
  right: 0;
  width: 80vw;
  max-width: 320px;
  height: 100%;
  z-index: 999;
  background-color: #fff;
  flex-direction: column;
  align-items: stretch;
  justify-content: flex-start;
  opacity: 0;
  pointer-events: none;
  transform: translateX(100%);
  transition: opacity var(--dur-base) var(--ease-out),
              transform var(--dur-base) var(--ease-out);
  box-shadow: -4px 0 24px rgba(0,0,0,0.15);
}

.nav-drawer.is-open {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(0);
}

.nav-drawer__header {
  background-color: var(--color-accent);
  padding: 14px 20px;
}

.nav-drawer__header-label {
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.nav-drawer__link {
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  color: #333;
  letter-spacing: 0.04em;
  text-decoration: none;
  padding: 16px 20px;
  border-bottom: 1px solid #e8e8e8;
  display: flex;
  align-items: center;
  transition: background-color var(--dur-fast), color var(--dur-fast);
}

.nav-drawer__link::before {
  content: "›";
  margin-right: 10px;
  font-size: 1.1rem;
  color: #999;
}

.nav-drawer__link:hover {
  background-color: #f5f5f5;
  color: var(--color-accent);
}

.nav-drawer__link.is-active {
  background-color: #f9f9f9;
  color: var(--color-accent);
}

.nav-drawer__cta {
  margin: var(--sp-5) 20px;
  padding: 14px 20px;
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: #fff;
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
  text-align: center;
  text-decoration: none;
  display: block;
}

.nav-drawer__cta:hover {
  opacity: 0.85;
}

/* ドロワー背景オーバーレイ */
.nav-drawer-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 998;
  background-color: rgba(0, 0, 0, 0.5);
  opacity: 0;
  transition: opacity var(--dur-base) var(--ease-out);
}

.nav-drawer-overlay.is-open {
  opacity: 1;
}

/* ------------------------------------------------------------
   8. Footer
   ------------------------------------------------------------ */
.footer {
  background-color: var(--color-bg-warm);
  border-top: 1px solid var(--color-border);
  padding-block: var(--sp-8) var(--sp-5);
}

.footer__inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--sp-8);
  align-items: start;
  margin-bottom: var(--sp-8);
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--sp-4);
}

.footer__brand-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: 1.5px solid var(--color-accent);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 900;
  color: var(--color-accent);
}

.footer__tagline {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  max-width: 320px;
}

.footer__nav {
  display: flex;
  gap: var(--sp-8);
}

.footer__nav-group h4 {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-gold);
  margin-bottom: var(--sp-4);
}

.footer__nav-group ul {
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}

.footer__nav-group a {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  transition: color var(--dur-fast);
}

.footer__nav-group a:hover {
  color: var(--color-text);
}

.footer__bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--color-border);
  padding-top: var(--sp-5);
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.footer__bottom-links {
  display: flex;
  gap: var(--sp-5);
}

.footer__bottom-links a {
  color: var(--color-text-muted);
  transition: color var(--dur-fast);
}

.footer__bottom-links a:hover {
  color: var(--color-text);
}

/* ------------------------------------------------------------
   9. Fade-in Animation (Intersection Observer)
   ------------------------------------------------------------ */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
}

.fade-in.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger delays for child elements */
.fade-in--delay-1 { transition-delay: 80ms; }
.fade-in--delay-2 { transition-delay: 160ms; }
.fade-in--delay-3 { transition-delay: 240ms; }
.fade-in--delay-4 { transition-delay: 320ms; }
.fade-in--delay-5 { transition-delay: 400ms; }

/* Slide from left/right variants */
.fade-in--left {
  transform: translateX(-24px);
}

.fade-in--right {
  transform: translateX(24px);
}

.fade-in--left.is-visible,
.fade-in--right.is-visible {
  transform: translateX(0);
}

/* Scale variant */
.fade-in--scale {
  transform: scale(0.96);
}

.fade-in--scale.is-visible {
  transform: scale(1);
}

/* ------------------------------------------------------------
   10. Common UI Components
   ------------------------------------------------------------ */

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  padding: 13px 32px;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: none;
  text-decoration: none;
  transition: background-color var(--dur-fast), color var(--dur-fast),
              transform var(--dur-fast), box-shadow var(--dur-fast);
  white-space: nowrap;
}

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

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

.btn--primary:hover {
  background-color: var(--color-accent-light);
  box-shadow: var(--shadow-glow);
}

.btn--outline {
  background-color: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}

.btn--outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.btn--gold {
  background-color: transparent;
  color: var(--color-gold);
  border: 1.5px solid var(--color-gold);
}

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

.btn--lg {
  padding: 16px 44px;
  font-size: 0.95rem;
}

.btn--sm {
  padding: 8px 20px;
  font-size: 0.78rem;
}

/* --- Cards --- */
.card {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--dur-base), box-shadow var(--dur-base),
              transform var(--dur-base) var(--ease-out);
}

.card:hover {
  border-color: rgba(200, 68, 42, 0.35);
  box-shadow: var(--shadow-card);
  transform: translateY(-4px);
}

/* --- Tag / Badge --- */
.tag {
  display: inline-block;
  padding: 3px 10px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border-radius: 2px;
}

.tag--accent {
  background-color: rgba(200, 68, 42, 0.15);
  color: var(--color-accent-light);
  border: 1px solid rgba(200, 68, 42, 0.3);
}

.tag--gold {
  background-color: rgba(184, 164, 114, 0.12);
  color: var(--color-gold);
  border: 1px solid rgba(184, 164, 114, 0.25);
}

.tag--muted {
  background-color: rgba(255, 255, 255, 0.05);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}

/* --- Divider --- */
.divider {
  border: none;
  border-top: 1px solid var(--color-border);
}

/* --- Accent line --- */
.accent-line {
  display: block;
  width: 40px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold));
  border-radius: 2px;
}

/* --- Page hero (common across inner pages) --- */
.page-hero {
  padding-top: calc(var(--header-height) + var(--sp-9));
  padding-bottom: var(--sp-9);
  background-color: var(--color-bg-warm);
  border-bottom: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: -80px;
  right: -80px;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(200, 68, 42, 0.07) 0%, transparent 65%);
  pointer-events: none;
}

.page-hero__label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--sp-4);
}

.page-hero__title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900;
  color: var(--color-text);
  line-height: 1.15;
  margin-bottom: var(--sp-5);
}

.page-hero__desc {
  font-size: clamp(0.9rem, 1.5vw, 1.05rem);
  color: var(--color-text-muted);
  max-width: 560px;
  line-height: 1.85;
}

/* --- Breadcrumb --- */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-bottom: var(--sp-5);
}

.breadcrumb a {
  color: var(--color-text-muted);
  transition: color var(--dur-fast);
}

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

.breadcrumb__sep {
  color: var(--color-border);
}

/* --- Scroll to top button --- */
.scroll-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  z-index: 500;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-muted);
  font-size: 1.1rem;
  cursor: pointer;
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: opacity var(--dur-base), transform var(--dur-base),
              border-color var(--dur-fast), color var(--dur-fast);
}

.scroll-top.is-visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.scroll-top:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ------------------------------------------------------------
   11. Responsive — 900px breakpoint
   ------------------------------------------------------------ */
@media (max-width: 900px) {
  :root {
    --header-height: 64px;
    --content-pad: clamp(16px, 4vw, 40px);
  }

  .header__nav,
  .header__cta {
    display: none;
  }

  /* 3-column grid: [hamburger 44px] [logo 1fr centered] [spacer 44px] */
  .header__inner {
    display: grid;
    grid-template-columns: 44px 1fr 44px;
  }

  .hamburger {
    display: flex;
    order: -1;
  }

  .header__logo {
    justify-content: center;
  }

  .nav-drawer {
    display: flex;
  }

  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer__inner {
    grid-template-columns: 1fr;
    gap: var(--sp-6);
  }

  .footer__nav {
    flex-wrap: wrap;
    gap: var(--sp-6);
  }

  .footer__bottom {
    flex-direction: column;
    gap: var(--sp-3);
    text-align: center;
  }
}

/* ------------------------------------------------------------
   12. Responsive — 600px breakpoint
   ------------------------------------------------------------ */
@media (max-width: 600px) {
  :root {
    --sp-9: 72px;
    --sp-10: 96px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .section {
    padding-block: var(--sp-9);
  }

  .btn--lg {
    padding: 14px 32px;
  }

  .scroll-top {
    bottom: 20px;
    right: 20px;
  }
}

/* ------------------------------------------------------------
   13. Accessibility & reduced motion
   ------------------------------------------------------------ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .fade-in {
    opacity: 1;
    transform: none;
  }
}

/* Focus styles */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* Selection */
::selection {
  background-color: rgba(200, 68, 42, 0.35);
  color: var(--color-text);
}