hr {
  border-color: #dee2e6;
  opacity: 1;
}

p {
  margin: 2rem 0;
}
p a {
  text-decoration: underline;
}

blockquote {
  font-style: italic;
  color: #6c757d;
}

.btn {
  letter-spacing: 0.0625em;
}

.form-floating input,
.form-floating textarea {
  border-left: 0;
  border-right: 0;
  border-top: 0;
}
.form-floating input:focus,
.form-floating textarea:focus {
  box-shadow: none;
}
.form-floating label {
  color: #6c757d;
}

#mainNav {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1030;
  border-bottom: 1px solid #dee2e6;
  background-color: #fff;
  font-family: "Open Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
}
#mainNav .navbar-brand {
  font-weight: 800;
}
#mainNav .navbar-toggler {
  font-size: 0.75rem;
  font-weight: 800;
  padding: 0.75rem;
  text-transform: uppercase;
}
#mainNav .navbar-nav > li.nav-item > a.nav-link {
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.0625em;
  text-transform: uppercase;
}
@media (min-width: 992px) {
  #mainNav {
    border-bottom: 1px solid transparent;
    background: transparent;
  }
  #mainNav .navbar-brand {
    color: #fff;
  }
  #mainNav .navbar-brand:focus, #mainNav .navbar-brand:hover {
    color: rgba(255, 255, 255, 0.8);
  }
  #mainNav .navbar-nav > li.nav-item > a.nav-link {
    color: #fff;
  }
  #mainNav .navbar-nav > li.nav-item > a.nav-link:focus, #mainNav .navbar-nav > li.nav-item > a.nav-link:hover {
    color: rgba(255, 255, 255, 0.8);
  }
}
@media (min-width: 992px) {
  #mainNav {
    transition: background-color 0.2s;
    /* Force Hardware Acceleration in WebKit */
    transform: translate3d(0, 0, 0);
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
  }
  #mainNav.is-fixed {
    /* when the user scrolls down, we hide the header right above the viewport */
    position: fixed;
    top: -83px;
    transition: transform 0.2s;
    border-bottom: 1px solid white;
    background-color: rgba(255, 255, 255, 0.9);
  }
  #mainNav.is-fixed .navbar-brand {
    color: #212529;
  }
  #mainNav.is-fixed .navbar-brand:focus, #mainNav.is-fixed .navbar-brand:hover {
    color: #0085A1;
  }
  #mainNav.is-fixed .navbar-nav > li.nav-item > a {
    color: #212529;
  }
  #mainNav.is-fixed .navbar-nav > li.nav-item > a:focus, #mainNav.is-fixed .navbar-nav > li.nav-item > a:hover {
    color: #0085A1;
  }
  #mainNav.is-visible {
    /* if the user changes the scrolling direction, we show the header */
    transform: translate3d(0, 100%, 0);
  }
}

footer {
  padding-top: 3rem;
  padding-bottom: 3rem;
}

header.masthead {
  position: relative;
  margin-bottom: 3rem;
  padding-top: calc(8rem + 57px);
  padding-bottom: 8rem;
  width: 100%;
  background: no-repeat center center;
  background-color: #6c757d;
  background-size: cover;
  background-attachment: scroll;
}
header.masthead:before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #212529;
  opacity: 0.5;
  z-index: 1;
}
header.masthead .page-heading,
header.masthead .post-heading,
header.masthead .site-heading {
  color: #fff;
}
header.masthead .page-heading,
header.masthead .site-heading {
  text-align: center;
}
header.masthead .page-heading h1, header.masthead .page-heading .h1,
header.masthead .site-heading h1,
header.masthead .site-heading .h1 {
  font-size: 3rem;
}
header.masthead .page-heading .subheading,
header.masthead .site-heading .subheading {
  font-size: 1.5rem;
  font-weight: 300;
  line-height: 1.1;
  display: block;
  margin-top: 0.625rem;
  font-family: "Open Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
}
header.masthead .post-heading h1, header.masthead .post-heading .h1 {
  font-size: 2.25rem;
}
header.masthead .post-heading .meta,
header.masthead .post-heading .subheading {
  line-height: 1.1;
  display: block;
}
header.masthead .post-heading .subheading {
  font-size: 1.5rem;
  font-weight: 600;
  margin: 0.75rem 0 2rem;
  font-family: "Open Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
}
header.masthead .post-heading .meta {
  font-size: 1.25rem;
  font-weight: 300;
  font-style: italic;
  font-family: "Lora", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
}
header.masthead .post-heading .meta a {
  color: #fff;
}
@media (min-width: 992px) {
  header.masthead {
    padding-top: 12.5rem;
    padding-bottom: 12.5rem;
  }
  header.masthead .page-heading h1, header.masthead .page-heading .h1,
  header.masthead .site-heading h1,
  header.masthead .site-heading .h1 {
    font-size: 5rem;
  }
  header.masthead .post-heading h1, header.masthead .post-heading .h1 {
    font-size: 3.5rem;
  }
  header.masthead .post-heading .subheading {
    font-size: 1.875rem;
  }
}

header.masthead .masthead-bg {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  z-index: 0;
}

header.masthead > .container {
  position: relative;
  z-index: 2;
}

.section-heading {
  font-size: 2.25rem;
  font-weight: 700;
  margin-top: 3.75rem;
}

.caption {
  font-size: 0.875rem;
  font-style: italic;
  display: block;
  margin: 0;
  padding: 0.625rem;
  text-align: center;
}

.post-preview > a {
  color: #212529;
}
.post-preview > a:focus, .post-preview > a:hover {
  text-decoration: none;
  color: #0085A1;
}
.post-preview > a > .post-title {
  font-size: 1.875rem;
  margin-top: 1.875rem;
  margin-bottom: 0.625rem;
}
.post-preview > a > .post-subtitle {
  font-weight: 300;
  margin-bottom: 0.625rem;
}
.post-preview > .post-meta {
  font-size: 1.125rem;
  font-style: italic;
  margin-top: 0;
  color: #6c757d;
}
.post-preview > .post-meta > a {
  text-decoration: none;
}
@media (min-width: 992px) {
  .post-preview > a > .post-title {
    font-size: 2.25rem;
  }
}

body {
  font-family: "Open Sans", "Lora", serif;
  font-size: 1.3rem;
  line-height: 1.6;
  color: #222;
}

.masthead {
  background-repeat: no-repeat;
  background-position: center 0%;
  background-size: cover;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 4rem 0;
  position: relative;
  color: #fff;
}
@media (min-width: 992px) {
  .masthead { min-height: 82vh; padding: 6rem 0; }
}

.masthead::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.28);
  z-index: 0;
}
.masthead .site-heading { position: relative; z-index: 1; }

.site-heading h1 {
  font-size: 1rem;    /* 约 28px */
  margin: 0 0 0.5rem 0;
  line-height: 1.05;
}
@media (min-width: 768px) {
  .site-heading h1 { font-size: 2rem; }
}
.site-heading .subheading {
  font-size: 1.125rem;
  display: block;
}


.post-title { font-size: 1rem; }        /* 28px 左右 */
.post-subtitle { font-size: 1rem; color: #555; }
.post-meta { font-size: 0.9rem; color: #777; }

@media (max-width: 576px) {
  .site-heading h1 { font-size: 1.6rem; }
  .site-heading .subheading { font-size: 0.95rem; }
  .masthead { min-height: 55vh; padding: 3rem 0; }
}