:root {
  /* Colors: Primary */
  --color-primary: #2487ce;
  --color-on-primary: #FFFFFF;
  --color-primary-container: #E4DFFF;
  --color-on-primary-container: #00006C;

  /* Colors: Secondary */
  --color-secondary: #3D84B6;
  --color-on-secondary: #FFFFFF;
  --color-secondary-container: #E5DFFF;
  --color-on-secondary-container: #1D184A;

  /* Colors: Tertiary */
  --color-tertiary: #7E5260;
  --color-on-tertiary: #FFFFFF;
  --color-tertiary-container: #FFD9E4;
  --color-on-tertiary-container: #31101D;

  /* Colors: Error */
  --color-error: #BA1A1A;
  --color-on-error: #FFFFFF;
  --color-error-container: #FFDAD6;
  --color-on-error-container: #410002;

  /* Colors: Neutral */
  --color-background: #FFFFFF;
  --color-on-background: #1C1B1F;
  --color-surface: #FFFFFF;
  --color-on-surface: #1C1B1F;
  --color-surface-variant: #E4E1EC;
  --color-on-surface-variant: #48464F;
  --color-outline: #cdd8e0;
  --color-shadow: #000000;
  --color-inverse-surface: #313034;
  /** --color-inverse-on-surface: #F4EFF4; **/
  --color-inverse-on-surface: #e6f1f3;
  --color-inverse-primary: #C5C0FF;


  /* Spacing */
  --spacing-xs: 0.25rem;
  /* Example */
  --spacing-sm: 0.5rem;
  /* Example */
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 4rem;
  --spacing-xxl: 5rem;
  --spacing-xxxl: 6rem;

  /* Typography */
  --font-size-h1-lg: 3rem;
  --font-size-h1-md: 2.5rem;

  /* Sizes */
  --speaker-image-size: 240px;
  --map-placeholder-height: 300px;

  /* Hero Section */
  --hero-min-height-lg: 60vh;
  --hero-min-height-md: 50vh;
  --hero-padding-lg: var(--spacing-xxxl) 0;
  --hero-padding-md: var(--spacing-xl) 0;

  /* Card */
  --card-hover-translate-y: -5px;
  --card-hover-box-shadow: 0 8px 15px var(--color-shadow);


}

:root {
  /* Bootstrap Variables */
  --bs-primary: var(--color-primary);
  --bs-btn-bg: var(--color-primary);
}

* {
  font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
}


/* Hero Section Styling */
.hero-section {
  /* 画像を指定する場合 */
  /* background: linear-gradient(var(--color-shadow-hero), var(--color-shadow-hero)), url('your-hero-image.jpg') no-repeat center center; */
  /* background-size: cover; */

  /* 単色やグラデーションを指定する場合 */
  background: linear-gradient(45deg, var(--color-primary), #0055a4);
  /* 大学のテーマカラーなどに合わせて調整 */
  min-height: var(--hero-min-height-lg);
  /* 高さを調整 */
  padding: var(--hero-padding-lg);
  /* 上下の余白 */
}

.hero-section h1 {
  font-size: var(--font-size-h1-lg);
  /* Adjust as needed */
}

/* Smooth Scrolling (Optional but recommended for single-page sites) */
html {
  scroll-padding-top: 80px; /* Offset for sticky navbar */
}
@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

/* Skip link */
.skip-link:focus {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 1050;
  padding: 1rem;
  background-color: var(--color-primary);
  color: var(--color-on-primary);
  font-weight: bold;
  text-decoration: none;
  border-radius: var(--bs-border-radius);
  margin: 1rem;
}

.color-bg-light {
  background-color: var(--color-inverse-on-surface);
}

/* Reveal Background Animation */
.reveal-bg {
  background-color: transparent !important;
  transition: background-color 1.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal-bg.is-visible {
  background-color: var(--color-inverse-on-surface) !important;
}

/* Speaker Image Styling */
.speaker-img {
  width: var(--speaker-image-size);
  /* 画像サイズ */
  height: var(--speaker-image-size);
  object-fit: cover;
  /* 画像のアスペクト比を保ちつつ切り取る */
  border-radius: 50%;
  /* 円形にする */
  margin: var(--spacing-lg) auto var(--spacing-md) auto;
  /* 上下のマージン調整 */
  border: 3px solid var(--color-border-light);
  /* 枠線 */
}

/* Card Styling Adjustments */
.card.speaker {
  /* border: none; */
  /* カードの枠線を消す場合 */
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card.speaker:hover {
  transform: translateY(var(--card-hover-translate-y));
  /* ホバー時に少し浮き上がる */
  box-shadow: var(--card-hover-box-shadow);
  /* 影を少し濃くする */
}


/* Map Placeholder Styling */
.map-placeholder {
  height: var(--map-placeholder-height);
  /* 地図の高さを指定 */
  border-radius: var(--bs-border-radius);
  /* Bootstrapの角丸に合わせる */
}

/* Navbar Styling Adjustment */
.navbar-brand {
  font-weight: bold;
}

/** about **/
.about__read {
  text-indent: 1em;
  line-height: 1.75;
}

/* Footer Styling */
footer a {
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

/** heading */
h2 {
  font-size: 1.96rem;
}

h3 {
  font-size: 1.4rem;
}

h4 {
  font-size: 1.2rem;
}

/** dl,dt,dd Basic Style **/
dl {
  background-color: var(--color-on-primary);
  border-style: solid;
  border-color: var(--color-outline);
  border-width: 1px 0 0;
}

dt,
dd {
  border-style: solid;
  border-color: var(--color-outline);
  border-width: 0;
  padding: .75em;
  font-weight: normal;
  margin: 0;
  box-sizing: border-box;
}

dt {
  background-color: var(--color-secondary);
  color: var(--color-on-secondary);
  border-width: 0 1px 1px;

}

dd {
  border-width: 0 1px 1px 0px;
}

.program__table dt,
.program__table dd {
  display: grid;
  align-items: center;
}

/** footer **/
footer {
  background-color: var(--color-primary);
  color: var(--color-on-primary);
}

/** toggler */
.btn__toggler {
  display: inline-block;
  border: none;
  background: transparent;
  box-shadow: none;
  padding: .25em;
}

.btn__toggler:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

/** access **/

/** hero title **/
.hero-title-sub {
  display: inline-block;
  margin-top: 0.75em;
}

/* Responsive Adjustments */
@media (max-width: 768px) {

  .hero-title-main {
      font-size: 21px;
    }
  
    .hero-title-sub {
      display: block;
      margin-top: 1em;
      font-size: 18px;
      line-height: 1.25;
    }
  .eyecatch {
    width: 100%;
    height: 300px;
  }

  .eyecatch img {
    width: 100%;
    height: 300px;
    object-fit: cover;
  }

  .hero-section h1 {
    font-size: var(--font-size-h1-md);
  }

  .hero-section {
    min-height: var(--hero-min-height-md);
    padding: var(--hero-padding-md);
  }

  /** about **/
  .about__table,
  .program__table {
    margin: 0;
  }

  .about__table dt,
  .about__table dd,
  .program__table dt,
  .program__table dd {
    border-left-width: 1px;
    font-size: .95em;
  }

  .about__table dt {
    border-bottom-width: 0px;
    padding: .5em .7em;
  }

  .about__table dd {
    padding-bottom: 1.25em;
  }

  /** program **/
  .program__table dd {
    border-bottom-width: 0px;
  }

  .program__table dd+dd {
    border-top-style: dotted;
    border-top-width: 1px;
    padding-bottom: 1.75em;
  }

  .program__table dd:last-child {
    border-bottom-width: 1px;
  }

  .program__table .list-group>.list-group-item {
    padding-left: .5em;
    padding-right: .5em;
  }
}

/* PC */
@media (min-width: 992px) {

  br.br-sp {
    display: none;
  }

  #offcanvasNavbar.offcanvas {
    position: static !important;
    visibility: visible !important;
    transform: none !important;
    width: auto !important;
    background-color: transparent !important;
    border: none !important;
  }

  #offcanvasNavbar .offcanvas-header {
    display: none !important;
  }

  #offcanvasNavbar .offcanvas-body {
    display: flex;
    padding: 0;
    overflow-y: visible;
  }

  #offcanvasNavbar .navbar-nav {
    flex-direction: row;
    /* リンクを横に並べる */
    margin-left: auto;
    /* 右寄せ */
  }

  #offcanvasNavbar .nav-item {
    margin-left: var(--spacing-md);
    /* リンク間のスペース */
  }

  #offcanvasNavbar .nav-link {
    padding-right: 0;
    padding-left: 0;
  }

  .eyecatch {
    width: 100%;
    height: 500px;
  }

  .eyecatch img {
    width: 100%;
    height: 500px;
    object-fit: cover;
  }

  .program__table .list-group>.list-group-item {
    padding-left: .5em;
    padding-right: .5em;
  }

  .program__table dd {}

  .program__table dd+dd {
    display: flex;
    align-items: center;
  }

}

/* Section Focus Accessibility */
section[tabindex="-1"]:focus:not(:focus-visible),
main[tabindex="-1"]:focus:not(:focus-visible) {
  outline: none;
}

/* Focus Accessibility for Navigation */
.navbar-brand:focus-visible,
.nav-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

/* Active Nav Link Styling for Scrollspy */
@media (min-width: 992px) {
  .navbar-nav .nav-link.active {
    color: var(--bs-primary) !important;
    font-weight: bold;
    position: relative;
  }

  .navbar-nav .nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--bs-primary);
  }
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 3.5rem;
  height: 3.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  z-index: 1040;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease, background-color 0.2s;
  background-color: var(--color-background);
  border: 1px solid var(--color-outline);
  color: rgba(0, 0, 0, 0.55); /* Bootstrap .navbar-light .nav-link color */
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--color-background);
  color: var(--color-on-surface-variant);
  border-color: var(--color-outline);
}

@media (max-width: 768px) {
  .back-to-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 3rem;
    height: 3rem;
    font-size: 1.25rem;
  }
}