/* =========================================================================
   Spark Cube Studio — Stylesheet
   Minimalist, professional, single-page studio website.
   ========================================================================= */

:root {
  --bg: #ffffff;
  --bg-soft: #f6f7fb;
  --bg-elevated: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --text-subtle: #64748b;
  --accent: #5b6cff;
  --accent-strong: #4453e6;
  --accent-soft: #eef0ff;
  --border: #e5e7eb;
  --border-strong: #d1d5db;
  --radius-sm: 8px;
  --radius: 14px;
  --radius-lg: 20px;
  --max-w: 1200px;

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 4px 18px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 18px 40px rgba(15, 23, 42, 0.08);

  --duration: 240ms;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  font-family: 'Inter', 'Noto Sans SC', 'Noto Sans JP', 'Segoe UI', system-ui,
    -apple-system, BlinkMacSystemFont, 'Helvetica Neue', 'PingFang SC',
    'Hiragino Sans', 'Microsoft YaHei', 'Yu Gothic', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

html[lang^="zh"] body {
  font-family: 'Inter', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei',
    'Segoe UI', system-ui, -apple-system, sans-serif;
}

html[lang^="ja"] body {
  font-family: 'Inter', 'Noto Sans JP', 'Hiragino Sans', 'Hiragino Kaku Gothic ProN',
    'Yu Gothic', 'Meiryo', system-ui, -apple-system, sans-serif;
}

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

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

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

h1, h2, h3 {
  margin: 0 0 0.5em;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text);
}

p {
  margin: 0 0 1em;
  color: var(--text-muted);
}

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

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

.skip-link {
  position: absolute;
  top: -40px;
  left: 16px;
  background: var(--text);
  color: #fff;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  z-index: 1000;
  transition: top var(--duration) var(--ease);
}

.skip-link:focus {
  top: 12px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.01em;
  transition: transform var(--duration) var(--ease),
    background-color var(--duration) var(--ease),
    box-shadow var(--duration) var(--ease),
    border-color var(--duration) var(--ease),
    color var(--duration) var(--ease);
  white-space: nowrap;
}

.btn-primary {
  background: var(--text);
  color: #fff;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-strong);
}

.btn-ghost:hover {
  border-color: var(--text);
  transform: translateY(-1px);
}

.btn-lg {
  padding: 16px 28px;
  font-size: 1rem;
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.78);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--duration) var(--ease),
    background-color var(--duration) var(--ease);
}

.site-header.is-scrolled {
  border-bottom-color: var(--border);
  background: rgba(255, 255, 255, 0.92);
}

.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  text-decoration: none;
}

.brand-logo {
  height: 32px;
  width: auto;
  flex-shrink: 0;
}

.brand-text {
  display: inline-flex;
  align-items: baseline;
  gap: 0.22em;
  font-size: 1rem;
  line-height: 1;
  white-space: nowrap;
  user-select: none;
}

.brand-main {
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}

.brand-sub {
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: -0.01em;
}

.primary-nav {
  flex: 1;
  display: flex;
  justify-content: flex-end;
}

.primary-nav .nav-list {
  display: flex;
  align-items: center;
  gap: 8px;
}

.primary-nav a {
  display: inline-block;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--duration) var(--ease),
    background-color var(--duration) var(--ease);
}

.primary-nav a:hover,
.primary-nav a:focus-visible {
  color: var(--text);
  background: var(--bg-soft);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.nav-cta {
  padding: 10px 18px;
  font-size: 0.9rem;
}

/* ---------- Language switcher ---------- */
.lang-switch {
  position: relative;
}

.lang-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: transparent;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.85rem;
  letter-spacing: 0.01em;
  transition: color var(--duration) var(--ease),
    background-color var(--duration) var(--ease),
    border-color var(--duration) var(--ease);
}

.lang-btn:hover,
.lang-btn:focus-visible {
  color: var(--text);
  border-color: var(--border-strong);
  background: var(--bg-soft);
}

.lang-icon {
  flex-shrink: 0;
  opacity: 0.85;
}

.lang-current {
  min-width: 1.4em;
  text-align: center;
}

.lang-caret {
  flex-shrink: 0;
  opacity: 0.7;
  transition: transform var(--duration) var(--ease);
}

.lang-switch.is-open .lang-caret {
  transform: rotate(180deg);
}

.lang-switch.is-open .lang-btn {
  color: var(--text);
  border-color: var(--border-strong);
  background: var(--bg-soft);
}

.lang-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 180px;
  padding: 6px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  z-index: 60;
  display: flex;
  flex-direction: column;
  gap: 2px;
  animation: lang-menu-in 180ms var(--ease);
}

.lang-menu[hidden] {
  display: none;
}

@keyframes lang-menu-in {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.lang-menu li {
  display: block;
}

.lang-menu button {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 0.92rem;
  font-weight: 500;
  text-align: left;
  transition: background-color var(--duration) var(--ease),
    color var(--duration) var(--ease);
}

.lang-menu button:hover,
.lang-menu button:focus-visible {
  background: var(--bg-soft);
}

.lang-menu button.is-active {
  color: var(--accent-strong);
  background: var(--accent-soft);
}

.lang-code {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 22px;
  border-radius: 6px;
  background: var(--bg-soft);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.lang-menu button.is-active .lang-code {
  background: var(--accent);
  color: #fff;
}

.lang-name {
  flex: 1;
}

/* Mobile toggle */
.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  border: 1px solid var(--border);
}

.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--duration) var(--ease),
    opacity var(--duration) var(--ease);
}

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

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

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

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: 96px 0 80px;
  background: radial-gradient(
      1200px 600px at 80% -10%,
      rgba(91, 108, 255, 0.10),
      transparent 60%
    ),
    radial-gradient(
      900px 500px at 0% 20%,
      rgba(139, 92, 246, 0.08),
      transparent 60%
    ),
    var(--bg);
}

.hero-inner {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 880px;
}

.eyebrow {
  display: inline-block;
  padding: 6px 14px;
  margin-bottom: 28px;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-strong);
  background: var(--accent-soft);
  border-radius: 999px;
}

.hero-title {
  font-size: clamp(2.4rem, 6vw, 4.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.05;
  margin-bottom: 24px;
}

.hero-sub {
  font-size: clamp(1.05rem, 1.4vw, 1.2rem);
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 auto 40px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 64px;
}

.hero-meta {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
  max-width: 720px;
  margin: 0 auto;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.hero-meta > div {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 4px;
}

.meta-num {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
}

.meta-label {
  font-size: 0.85rem;
  color: var(--text-subtle);
}

/* Decorative orbs */
.hero-orbs {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 1;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.5;
}

.orb-1 {
  width: 320px;
  height: 320px;
  top: -80px;
  right: -60px;
  background: radial-gradient(circle, #8b5cf6, transparent 70%);
}

.orb-2 {
  width: 280px;
  height: 280px;
  bottom: -100px;
  left: -60px;
  background: radial-gradient(circle, #5b6cff, transparent 70%);
  opacity: 0.4;
}

.orb-3 {
  width: 200px;
  height: 200px;
  top: 40%;
  left: 50%;
  transform: translateX(-50%);
  background: radial-gradient(circle, #06b6d4, transparent 70%);
  opacity: 0.18;
}

/* ---------- Sections ---------- */
.section {
  padding: 112px 0;
}

.section-head {
  max-width: 720px;
  margin: 0 auto 64px;
  text-align: center;
}

.section-eyebrow {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-strong);
  margin: 0 0 14px;
}

.section-title {
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-lead {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin-bottom: 0;
}

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

/* ---------- About ---------- */
.about {
  background: var(--bg-soft);
}

.about-grid {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 80px;
  align-items: start;
}

.about-intro .section-title {
  margin-bottom: 24px;
}

.value-list {
  display: grid;
  gap: 16px;
}

.value-card {
  position: relative;
  padding: 28px 28px 28px 32px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform var(--duration) var(--ease),
    box-shadow var(--duration) var(--ease),
    border-color var(--duration) var(--ease);
}

.value-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}

.value-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 4px 0 8px;
}

.value-card p {
  margin: 0;
  font-size: 0.98rem;
}

.value-index {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--accent-strong);
}

/* ---------- Games ---------- */
.game-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 28px;
}

.game-card {
  display: flex;
  flex-direction: column;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform var(--duration) var(--ease),
    box-shadow var(--duration) var(--ease),
    border-color var(--duration) var(--ease);
}

.game-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--border-strong);
}

.game-cover {
  position: relative;
  aspect-ratio: 5 / 3;
  overflow: hidden;
  background: var(--bg-soft);
}

.game-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 600ms var(--ease);
}

.game-card:hover .game-cover img {
  transform: scale(1.04);
}

.game-status {
  position: absolute;
  top: 14px;
  left: 14px;
  padding: 5px 12px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(6px);
  border-radius: 999px;
}

.game-body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex: 1;
}

.game-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 0;
}

.game-desc {
  margin: 0;
  font-size: 0.95rem;
  color: var(--text-muted);
  flex: 1;
}

.game-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 4px;
}

.tag {
  display: inline-block;
  padding: 4px 10px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-subtle);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
}

/* ---------- Contact ---------- */
.contact {
  background: var(--bg-soft);
}

.contact-inner {
  text-align: center;
  max-width: 680px;
  margin: 0 auto;
}

.contact-inner .btn {
  margin-top: 16px;
  font-family: 'Inter', monospace;
}

.contact-note {
  margin-top: 20px;
  font-size: 0.9rem;
  color: var(--text-subtle);
}

/* ---------- Footer ---------- */
.site-footer {
  padding: 56px 0 40px;
  border-top: 1px solid var(--border);
  background: var(--bg);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.2fr;
  gap: 40px;
  align-items: start;
}

.footer-brand-name {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
}

.footer-logo {
  height: 28px;
  flex-shrink: 0;
}

.footer-brand-name .brand-text {
  font-size: 0.95rem;
}

.footer-tagline {
  margin: 0;
  font-size: 0.92rem;
  color: var(--text-subtle);
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  align-items: center;
}

.footer-nav a {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--duration) var(--ease);
}

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

.footer-meta {
  text-align: right;
  font-size: 0.85rem;
  color: var(--text-subtle);
}

.footer-meta p {
  margin: 0;
  color: inherit;
}

.footer-entity {
  margin-top: 4px !important;
  font-size: 0.8rem;
  opacity: 0.85;
}

/* ---------- Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 700ms var(--ease), transform 700ms var(--ease);
  will-change: opacity, transform;
}

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

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }

  html {
    scroll-behavior: auto;
  }
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .game-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
  }

  .footer-meta {
    grid-column: 1 / -1;
    text-align: left;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 80px 0;
  }

  .hero {
    padding: 72px 0 64px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .nav-cta {
    display: none;
  }

  .nav-actions {
    gap: 8px;
  }

  .lang-btn {
    padding: 7px 10px;
    font-size: 0.82rem;
  }

  .lang-menu {
    right: 0;
    min-width: 200px;
  }

  .primary-nav {
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: saturate(180%) blur(12px);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    padding: 16px 24px 24px;
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--duration) var(--ease),
      transform var(--duration) var(--ease),
      visibility var(--duration) var(--ease);
  }

  .nav-open .primary-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .primary-nav .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }

  .primary-nav a {
    display: block;
    padding: 12px 14px;
    font-size: 1rem;
  }

  .hero-meta {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .game-grid {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-meta {
    text-align: left;
  }

  .value-card {
    padding: 24px;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }
}

/* ---------- Focus ---------- */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}