/* ============================================================
   nav.css — Navigation and palette switcher
   ============================================================ */

/* PC 端右侧 Let's talk 按钮：基础规则在媒体查询之前，不被覆盖 */
.nav__cta {
  display: none;
  align-items: center;
  padding: 0 22px;
  border-radius: 100px;
  background: var(--accent);
  color: #fff;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.01em;
  white-space: nowrap;
  transition: opacity 0.25s, transform 0.25s var(--ease);
}
.nav__cta:hover { opacity: 0.88; transform: translateY(-1px); }

.nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 80;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: clamp(14px, 2.4vw, 22px) clamp(16px, 5vw, 48px);
  color: #fff;
  transition: transform 0.95s cubic-bezier(0.65, 0, 0.35, 1);
  will-change: transform;
}
@media (min-width: 861px) {
  .nav { justify-content: flex-start; }
  /* 菜单胶囊 + CTA 整体居中 */
  .nav__group {
    position: absolute;
    left: 50%;
    top: clamp(14px, 2.4vw, 22px);
    transform: translateX(-50%);
    display: flex;
    align-items: stretch;   /* CTA 高度跟随胶囊 */
    gap: 8px;
    white-space: nowrap;
  }
  .nav__menu { white-space: nowrap; }
  /* 日/中文链接较长，收紧字号和 padding 防止胶囊换行 */
  :lang(ja) .nav__menu,
  :lang(zh) .nav__menu { font-size: 14px; gap: 0; }
  :lang(ja) .nav__menu a,
  :lang(zh) .nav__menu a { padding: 10px 16px; }
  /* PC：logo 移入菜单胶囊靠左，隐藏 header 里的独立 logo（提权覆盖基础 display） */
  .nav .nav__logo { display: none; }
  /* PC 端显示 CTA 按钮，紧贴胶囊右侧，高度由 stretch 决定 */
  .nav__cta { display: flex; align-items: center; }
}
@media (max-width: 860px) {
  .nav { justify-content: space-between; }
}
/* hidden when scrolling down, revealed when scrolling up */
/* 用足够大的固定位移（不依赖塌缩后的 nav 高度），确保绝对定位的菜单也被推出视口；
   只让父级 .nav 这一套 transform 做动画，两个方向对称 */
html.nav-hidden .nav { transform: translateY(calc(-100% - 90px)); }

/* shared pill surface */
.nav__logo, .nav__menu {
  background: rgba(20, 18, 16, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-radius: 100px;
}

.nav__logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.03em;
  padding: 0;
  /* 去掉原 logo 的胶囊外框（菜单的 pill 保留） */
  background: none;
  border: none;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

/* ---- logo TrueFocus (vanilla port) · 像素风，无框无装饰 ---- */
.nav__focus {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 2px;
  font-family: 'Bitcount Grid Single', system-ui, monospace;  /* 像素点阵字体（无光晕） */
  font-palette: --bitcount-white;  /* 覆盖 COLRv1 彩色调色板为纯白（定义见 main.css） */
  font-size: 22px;
}
.nav__focus-word { transition: filter 0.5s ease; }
.nav__focus-word--accent { color: var(--accent); }
/* 动画开启后：默认模糊，仅当前词清晰 */
.nav__focus.is-on .nav__focus-word { filter: blur(3px); }
.nav__focus.is-on .nav__focus-word.is-active { filter: blur(0); }
/* 红色聚焦边角框，跟随当前词移动 */
.nav__focus-frame {
  position: absolute; top: 0; left: 0;
  width: 0; height: 0;
  pointer-events: none;
  opacity: 0;
  transition: transform 0.5s ease, width 0.5s ease, height 0.5s ease, opacity 0.4s ease;
}
.nav__focus.is-on .nav__focus-frame { opacity: 1; }
.nav__focus-frame i {
  position: absolute; width: 6px; height: 6px;
  border: 2px solid var(--accent);
  filter: drop-shadow(0 0 3px var(--accent));
  border-radius: 2px;
}
.nav__focus-frame i:nth-child(1) { top: -5px; left: -5px; border-right: none; border-bottom: none; }
.nav__focus-frame i:nth-child(2) { top: -5px; right: -5px; border-left: none; border-bottom: none; }
.nav__focus-frame i:nth-child(3) { bottom: -5px; left: -5px; border-right: none; border-top: none; }
.nav__focus-frame i:nth-child(4) { bottom: -5px; right: -5px; border-left: none; border-top: none; }
.nav__mark {
  width: 20px; height: 20px;
  border-radius: 7px;
  background: linear-gradient(135deg, var(--grad-a), var(--grad-b));
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.14);
  flex: none;
}

.nav__menu {
  display: flex;
  align-items: center;
  gap: clamp(2px, 0.6vw, 6px);
  padding: 7px 30px;
  font-size: 13px;
  font-weight: 500;
}
.nav__menu a {
  padding: 7px 15px;
  border-radius: 100px;
  opacity: 0.82;
  transition: opacity 0.25s, background 0.25s;
}
.nav__menu a:hover { opacity: 1; background: rgba(255, 255, 255, 0.08); }
/* 菜单内 logo：只在菜单可见时出现（移动端整个菜单已隐藏，故无需单独隐藏） */
/* logo 与右侧链接之间加一条竖线分隔 */
.nav__menu .nav__menu-logo {
  display: inline-flex; align-items: center;
  padding-left: 6px;
  margin-right: clamp(8px, 1.2vw, 18px);
  border-radius: 0;
  opacity: 1;
}
.nav__menu .nav__menu-logo:hover { background: none; }


/* ---------- Hamburger (mobile only) ---------- */
.nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 52px; height: 52px;
  background: rgba(20, 18, 16, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-radius: 100px;
  padding: 16px;
  cursor: pointer;
}
.nav__hamburger span {
  display: block;
  width: 100%; height: 1px;
  background: #fff;
  border-radius: 1px;
  transition: transform 0.3s, opacity 0.3s;
}
.nav__hamburger:hover span { background: var(--accent); }

@media (max-width: 860px) {
  .nav__menu { display: none; }
  .nav__hamburger { display: flex; }
  .nav__logo { margin-left: 20px; }   /* 移动端 logo 往右移 */
}

/* ---------- Mobile menu overlay ---------- */
.nav__mobile {
  position: fixed; z-index: 79;
  inset: 0;
  background: rgba(10, 10, 10, 0.97);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: flex-start;
  gap: 40px;
  padding: clamp(90px, 14vw, 120px) clamp(20px, 5vw, 48px) 48px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.4s var(--ease), visibility 0.4s;
}
.nav__mobile.is-open { opacity: 1; visibility: visible; }
.nav__mobile-links {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
}
.nav__mobile-links a {
  font-size: clamp(2.0rem, 6vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--muted);
  padding: 10px 24px;
  border-radius: 100px;
  transition: color 0.25s, background 0.25s;
}
.nav__mobile-links a:hover,
.nav__mobile-links a:active {
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
}
.nav__mobile-cta {
  margin-top: 20px;
  margin-left: 18px;   /* ← 往右移，改这个值 */
  background: var(--accent) !important;
  color: #fff !important;
  font-family: 'Space Mono', var(--font-cjk), monospace;
  font-size: 20px !important;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
@media (min-width: 861px) {
  .nav__mobile { display: none; }
}

/* Hamburger → X animation */
.nav__hamburger.is-active span:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.nav__hamburger.is-active span:nth-child(2) {
  opacity: 0;
}
.nav__hamburger.is-active span:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* ---------- Mobile language selector (右下角 + 弹窗) ---------- */
.nav__langsel {
  position: absolute;
  left: 36px;
  bottom: clamp(28px, 7vw, 56px);
  z-index: 2;
}
.nav__langsel-trigger {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: 'Space Mono', var(--font-cjk), monospace;
  font-size: 12px; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--paper);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(242, 240, 235, 0.18);
  border-radius: 100px;
  padding: 10px 16px;
  cursor: pointer;
  transition: background 0.25s, border-color 0.25s;
}
.nav__langsel-trigger:hover { background: rgba(255, 255, 255, 0.1); }
.nav__langsel-caret { transition: transform 0.3s var(--ease); }
.nav__langsel.is-open .nav__langsel-caret { transform: rotate(180deg); }
.nav__langsel-pop {
  position: absolute;
  left: 0;
  bottom: calc(100% + 10px);   /* 向上弹出 */
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 100%;
  padding: 6px;
  background: rgba(20, 18, 16, 0.92);
  border: 1px solid rgba(242, 240, 235, 0.16);
  border-radius: 16px;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  opacity: 0; visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0.25s;
}
.nav__langsel.is-open .nav__langsel-pop { opacity: 1; visibility: visible; transform: translateY(0); }
.nav__langsel-pop .lang__btn { text-align: left; padding: 8px 14px; white-space: nowrap; }

/* ---------- Language switch (.lang__btn 用于 nav + footer 弹窗) ---------- */
.lang__btn {
  font-family: 'Space Mono', var(--font-cjk), monospace;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  background: none;
  border: 1px solid transparent;
  border-radius: 100px;
  padding: 4px 12px;
  cursor: pointer;
  transition: color 0.25s, border-color 0.25s;
}
.lang__btn:hover { color: var(--paper); }
.lang__btn.is-active { color: var(--paper); border-color: var(--line); }

/* ---------- Back to top ---------- */
.totop {
  position: fixed; z-index: 90;
  right: clamp(16px, 4vw, 40px);
  bottom: clamp(16px, 4vw, 36px);
  width: 46px; height: 46px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 50%;
  color: var(--paper);
  background: rgba(15, 15, 15, 0.7);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid rgba(242, 240, 235, 0.16);
  cursor: pointer;
  opacity: 0; visibility: hidden;
  transform: translateY(10px) scale(0.9);
  transition: opacity 0.3s var(--ease), transform 0.3s var(--ease), visibility 0.3s, background 0.25s, border-color 0.25s;
}
.totop svg { width: 18px; height: 18px; }
.totop:hover { background: var(--accent); border-color: transparent; }
.totop.is-visible { opacity: 1; visibility: visible; transform: translateY(0) scale(1); }