/*  Header  */
@media (min-width: 1099px) {
  header {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 250px;
    min-height: 100%;
    padding: 0 0 0 50px;
    /* Solid white collapsed rail (a clean 64px strip beside the covers). The
       idle ocean is now a separate full-page overlay (idle-ocean.js), not
       painted into this rail, so the header simply stays white. */
    background: #fff;
    float: left;
    overflow: hidden;
    z-index: 9999;
    transition: transform 0.3s ease;
    transition:
      transform 0.3s ease,
      opacity 0.3s ease,
      background 0.3s ease;
    /* Header border-box = width(250) + padding-left(50) = 300px. Showing exactly
       --rail px of it means translateX(--rail - 300). The collapsed .main reserves
       the same --rail, so the rail sits flush beside the content (no overlap). */
    transform: translateX(calc(var(--rail) - 300px));
    will-change: transform;
  }

  /* 当侧边栏收起时的文字透明度 */
  header .logo,
  header nav,
  header .footer,
  header .social,
  header a,
  header p,
  header .subtitle,
  header .description {
    transition: opacity 0.4s ease;
    opacity: 0.02;
  }

  header:hover,
  header.show_menu {
    transform: translateX(0);
    background: #fff;
    box-shadow: 2px 0 12px rgb(0, 0, 0, 0.1);
  }

  /* 当侧边栏展开时恢复文字透明度 */
  header:hover .logo,
  header:hover nav,
  header:hover .footer,
  header:hover .social,
  header:hover a,
  header:hover p,
  header:hover .subtitle,
  header:hover .description,
  header.show_menu .logo,
  header.show_menu nav,
  header.show_menu .footer,
  header.show_menu .social,
  header.show_menu a,
  header.show_menu p,
  header.show_menu .subtitle,
  header.show_menu .description {
    opacity: 1;
  }

  header .logo {
    margin-top: 100px;
    text-align: right;
    padding-right: 20px;
    width: 180px;
  }

  header .logo .subtitle {
    font-family:
      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.6em;
    color: #666;
    margin-top: 10px;
    line-height: 1;
    text-align: right;
    white-space: nowrap;
    letter-spacing: -0.2px;
    font-weight: 700;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  header .logo .description {
    font-family:
      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.8em;
    color: #888;
    margin-top: 15px;
    line-height: 1.5;
    text-align: right;
    font-weight: normal;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  header .logo a,
  header .logo a:active,
  header .logo a:visited {
    text-decoration: none;
    text-transform: uppercase;
    font-family:
      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    color: #454545;
    font-size: 1.5em;
    letter-spacing: 0.2em;
    white-space: nowrap;
    display: inline-block;
    font-weight: normal;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  header .logo a:hover {
    text-decoration: none;
    color: #969595;
    font-size: 1.5em;
  }

  header nav ul {
    display: block;
    overflow: hidden;
    margin-top: 100px;
    list-style: none;
  }

  header nav ul li {
    display: block;
    margin-bottom: 30px;
  }

  header nav ul li a {
    color: #454545;
    font-family:
      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 14px;
    text-decoration: none;
    letter-spacing: 1px;
  }

  header nav ul li a:hover,
  header nav ul li a.selected {
    color: #969595;
  }

  header .footer {
    position: absolute;
    bottom: 50px;
  }

  header ul.social {
    list-style: none;
    margin-bottom: 5px;
  }

  header ul.social li {
    display: block;
    float: left;
    position: relative;
    margin: 0 15px 15px 0;
  }

  /* Social-icon button chrome + glyph masks were moved OUT of this
     desktop-only block into the shared section at the bottom of this
     file, so the mobile overlay (responsive.css) renders the same
     icons. Desktop keeps only the list-level layout (.footer position,
     .social li float) above. */

  header .rights p {
    color: #454545;
    font-family:
      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 11px;
    letter-spacing: 1px;
    line-height: 18px;
  }

  header .rights a {
    font-family:
      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-weight: bold;
    text-decoration: none;
  }
  #menu_icon,
  .close_menu {
    display: none;
  }
}

/* ============================================================
   Shared social-icon styling (desktop sidebar + mobile overlay)
   Lives outside the breakpoint media queries so both layouts get
   the same icon buttons. Each `.social li a` is a square outline
   button; the brand glyph is a currentColor-tinted CSS mask, so
   hover/focus recolours both border and glyph in one step.
   ============================================================ */
header ul.social li a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border: 1px solid #d9d9d9;
  border-radius: 12px;
  color: #565656;
  background: transparent;
  position: relative;
}

header ul.social li a::before {
  content: '';
  display: block;
  width: 22px;
  height: 22px;
  background-color: currentColor;
  mask-repeat: no-repeat;
  mask-position: center;
  mask-size: contain;
  transition: transform 0.2s ease;
}

header ul.social li a:hover,
header ul.social li a:focus {
  color: var(--accent);
  border-color: var(--accent);
}

header ul.social li a:hover::before,
header ul.social li a:focus::before {
  transform: scale(1.1);
}

header ul.social li a.behance::before {
  mask-image: url('../../img/social/icon-bilibili.svg');
}
header ul.social li a.google::before {
  mask-image: url('../../img/social/icon-email.svg');
}
header ul.social li a.github::before {
  mask-image: url('../../img/social/icon-github.svg');
}
header ul.social li a.dribble::before {
  mask-image: url('../../img/social/icon-douban.svg');
}
header ul.social li a.rss::before {
  mask-image: url('../../img/social/icon-rss.svg');
}
header ul.social li a.instagram::before {
  mask-image: url('../../img/social/icon-instagram.svg');
}
header ul.social li a.language::before {
  mask-image: url('../../img/social/icon-language.svg');
}
header ul.social li a.youtube::before {
  mask-image: none;
}

/* The labelled EN · 中文 language control is a mobile-only affordance
   (responsive.css turns it on); on the desktop sidebar the globe icon
   in .social handles language, so keep it hidden by default. */
.lang-row {
  display: none;
}

/* Full-page idle ocean overlay (idle-ocean.js — homepage + desktop only).
   A fixed, click-through canvas that the "tide" washes across on idle. The
   wash-in / recede and its opacity are driven inside the shader (uReveal /
   uOpaqueMax); JS only toggles visibility, so no CSS transition is needed.
   Sits above the collapsed header so a full submerge has no white strip. */
.idle-ocean {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 10000;
}