/* ============================================
   KAZU SUZUKI GRAPHIC — Base Design System
   Inspired by Web Design Repertoire 2026
   Modern, Stylish, Animation-rich
============================================ */

:root {
  /* Monochrome Minimal */
  --color-bg: #0d0d0d;
  --color-bg-2: #1a1a1a;
  --color-bg-3: #222222;
  --color-bg-4: #050505;
  --color-text: #fafafa;
  --color-text-muted: rgba(250, 250, 250, 0.5);
  --color-text-invert: #0d0d0d;
  --color-accent: #ffffff;
  --color-accent-2: #e0e0e0;
  --color-accent-3: #cccccc;
  --color-border: rgba(255, 255, 255, 0.2);
  --color-border-dim: rgba(255, 255, 255, 0.08);
  --color-border-invert: rgba(0, 0, 0, 0.15);
  --color-primary: #ffffff;
  --color-primary-light: #dddddd;
  --transition: 0.5s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  --radius: 0px;
  --radius-lg: 0px;
  --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
  --font-sans: 'Inter', 'Noto Sans JP', sans-serif;
  --font-serif: 'Playfair Display', serif;
  --font-mono: 'Fira Code', monospace;
  --font-display: 'Inter', sans-serif;
  /* Minimal display font */
}

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

/* Global scroll background */
.scroll-bg {
  position: fixed;
  inset: -10vw;
  background-image: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.03) 0%, transparent 60%),
    linear-gradient(45deg, rgba(255, 255, 255, 0.01) 25%, transparent 25%, transparent 75%, rgba(255, 255, 255, 0.01) 75%, rgba(255, 255, 255, 0.01)),
    linear-gradient(45deg, rgba(255, 255, 255, 0.01) 25%, transparent 25%, transparent 75%, rgba(255, 255, 255, 0.01) 75%, rgba(255, 255, 255, 0.01));
  background-size: 100vw 100vh, 100px 100px, 100px 100px;
  background-position: 0 0, 0 0, 50px 50px;
  z-index: -1;
  pointer-events: none;
  transition: transform 0.1s linear;
}

/* ============================================
   SCROLL ANIMATIONS
============================================ */
[data-scroll-anim] {
  opacity: 0;
  transform: translateY(48px);
  transition: opacity 0.9s cubic-bezier(0.16, 1, 0.3, 1),
    transform 0.9s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-scroll-anim].is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Scale-in variant */
[data-scroll-anim="scale"] {
  transform: translateY(30px) scale(0.92);
}

[data-scroll-anim="scale"].is-visible {
  transform: translateY(0) scale(1);
}

/* Blur-clear variant */
[data-scroll-anim="blur"] {
  filter: blur(8px);
  transform: translateY(20px);
}

[data-scroll-anim="blur"].is-visible {
  filter: blur(0);
  transform: translateY(0);
  opacity: 1;
}

/* Reveal line */
[data-line] {
  display: block;
  height: 1px;
  width: 60px;
  background: linear-gradient(90deg, var(--color-accent), transparent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 1.2s cubic-bezier(0.16, 1, 0.3, 1);
  opacity: 0.8;
}

[data-line].is-visible {
  transform: scaleX(1);
}

/* ============================================
   NAV — Glassmorphism Sticky
============================================ */
.site-header {
  min-height: 72px;
  width: 100%;
  display: flex;
  align-items: center;
  background: rgba(13, 13, 13, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border-dim);
  position: fixed !important;
  top: 0;
  left: 0;
  z-index: 9999 !important;
  transition: background 0.4s ease, box-shadow 0.4s ease;
}

.site-header.scrolled {
  background: rgba(13, 13, 13, 0.98) !important;
  box-shadow: var(--shadow-md);
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 6%;
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
}

.logo {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 400;
  letter-spacing: 0.15em;
  cursor: pointer;
  flex-shrink: 0;
  color: var(--color-text);
  transition: color var(--transition), letter-spacing var(--transition);
}

.logo:hover {
  color: var(--color-accent);
  letter-spacing: 0.18em;
}

.logo span {
  color: var(--color-accent);
  font-style: italic;
  font-weight: 300;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 8px;
}

nav ul li {
  display: inline-block;
}

nav ul li a {
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  padding: 10px 16px;
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
}

nav ul li a::before {
  content: '';
  position: absolute;
  bottom: 8px;
  left: 16px;
  right: 16px;
  height: 1px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

nav ul li a:hover,
nav ul li a.is-active {
  color: var(--color-text);
}

nav ul li a:hover::before {
  transform: scaleX(1);
}

/* Slide-fill button */
.btn {
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  background: transparent;
  color: var(--color-text);
  padding: 12px 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
  isolation: isolate;
  transition: border-color var(--transition), color var(--transition);
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--color-text);
  transform: translateX(-101%);
  transition: transform 0.4s cubic-bezier(0.8, 0, 0.1, 1);
  z-index: -1;
}

.btn:hover {
  border-color: var(--color-text);
  color: #0d0d0d;
}

.btn:hover::before {
  transform: translateX(0);
}

/* Hamburger — Squeeze animation */
.hamburger-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--color-border-dim);
  border-radius: var(--radius);
  cursor: pointer;
  gap: 6px;
  padding: 0;
  z-index: 1001;
  transition: background var(--transition), border-color var(--transition);
}

.hamburger-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--color-accent);
}

.hamburger-btn__line {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1),
    opacity 0.35s ease,
    width 0.35s ease;
}

/* Squeeze to X */
.hamburger-btn.is-active .hamburger-btn__line:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.hamburger-btn.is-active .hamburger-btn__line:nth-child(2) {
  transform: scaleX(0);
  opacity: 0;
}

.hamburger-btn.is-active .hamburger-btn__line:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

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

/* ============================================
   FOOTER — Unified
============================================ */
footer {
  width: 100%;
  background: var(--color-bg);
  padding: 80px 6%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 16px;
  border-top: 1px solid var(--color-border-dim);
}

footer p:nth-child(1) {
  font-family: var(--font-display);
  font-size: 1.25rem;
  letter-spacing: 0.2em;
  color: var(--color-text);
}

footer p:nth-child(2) {
  font-size: 0.8rem;
  font-weight: 300;
  color: var(--color-text-muted);
  letter-spacing: 0.06em;
}

.social {
  display: flex;
  gap: 16px;
  margin: 20px 0;
}

.social a {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--color-border-dim);
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  transition: all var(--transition);
}

.social a:hover {
  background: var(--color-accent);
  border-color: var(--color-accent);
  transform: scale(1.12) translateY(-4px);
  box-shadow: 0 8px 24px rgba(196, 163, 90, 0.25);
}

.social a img {
  width: 20px;
  height: 20px;
  opacity: 0.8;
}

.social a:hover img {
  opacity: 1;
  filter: brightness(0);
}

.end {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  letter-spacing: 0.08em;
  margin-top: 8px;
  opacity: 0.6;
}

/* ============================================
   SHARED BUTTON STYLES
============================================ */
.button {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  background: transparent;
  padding: 12px 28px;
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
  isolation: isolate;
  cursor: pointer;
}

.button::before {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255, 255, 255, 0.1);
  transform: translateX(-101%);
  transition: transform 0.4s cubic-bezier(0.8, 0, 0.1, 1);
  z-index: -1;
}

.button:hover {
  border-color: var(--color-accent);
  color: var(--color-text);
}

.button:hover::before {
  transform: translateX(0);
}

/* ============================================
   RESPONSIVE — Nav / Hamburger
============================================ */
@media screen and (max-width: 768px) {
  .hamburger-btn {
    display: flex;
  }

  .nav-menu {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(13, 13, 13, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 36px;
    z-index: 1000;
  }

  .nav-menu.is-open {
    display: flex;
  }

  nav ul {
    flex-direction: column;
    align-items: center;
    gap: 8px;
  }

  nav ul li {
    padding: 12px 0;
  }

  nav ul li a {
    font-size: 0.95rem;
  }

  nav {
    padding: 18px 5%;
  }
}

@media screen and (max-width: 480px) {
  .logo {
    font-size: 1.1rem;
  }

  nav {
    padding: 16px 4%;
  }
}

/* ============================================
   REDUCED MOTION
============================================ */
@media (prefers-reduced-motion: reduce) {

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }

  [data-scroll-anim],
  [data-scroll-anim="scale"],
  [data-scroll-anim="blur"] {
    opacity: 1;
    transform: none;
    filter: none;
  }

  [data-line] {
    transform: scaleX(1);
  }
}