:root {
  --primary-color: #28B5E3;
  --gray-base: #6C757D;
  --gray-100: color-mix(in srgb, var(--gray-base), white 90%); /* 最淺 */
  --gray-200: color-mix(in srgb, var(--gray-base), white 75%);
  --gray-300: color-mix(in srgb, var(--gray-base), white 50%); /* 約等於 #ADB5BD */
  --gray-400: color-mix(in srgb, var(--gray-base), white 25%);
  --gray-500: var(--gray-base);
  --gray-600: color-mix(in srgb, var(--gray-base), black 15%);
  --gray-700: color-mix(in srgb, var(--gray-base), black 30%);
  --gray-800: color-mix(in srgb, var(--gray-base), black 50%);
  --gray-900: color-mix(in srgb, var(--gray-base), black 75%); /* 最深 */
  --main-radius: 12px;
}
body {
  text-autospace: normal;
  font-family: system-ui, -apple-system, Roboto, "Helvetica Neue", "Noto Sans TC", "Noto Sans", "Liberation Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
}
main{
  background-color: var(--gray-100);
}
.container {
  max-width: 1320px;
}
.text-primary-custom { color: var(--primary-color) !important; }
.bg-primary-custom { background-color: var(--primary-color) !important; }
.border-primary-custom { border-color: var(--primary-color) !important; }
.rounded-custom { border-radius: var(--main-radius); }
.fs-clamp-h1 { font-size: clamp(40px, 5vw, 80px); line-height: 1.2; }
.fs-clamp-h2 { font-size: clamp(20px, 3vw, 32px); }
.fs-clamp-h3 { font-size: clamp(24px, 4vw, 32px); }
.bg-light-white {
  background-color: rgba(255, 255, 255, 0.6);
}
.big-button-right-radius{
  border-bottom-right-radius: 40px;
}

/* Header Styles (Global) */
#header {
  --nav-default-color: var(--gray-500); 
  --nav-active-color: var(--primary-color);

  .navbar {
    background-color: #fff !important;
    position: relative;

    .container {
      /* 手機版需要 wrap 讓選單掉下來 */
      flex-wrap: wrap; 
    }
  }

  .nav-link {
    color: var(--nav-default-color) !important;
    text-decoration: none !important;
    transition: color 0.2s ease, box-shadow 0.2s ease;
    
    &:hover {
      color: var(--nav-active-color) !important;
    }

    &.active {
      color: var(--nav-active-color) !important;
      font-weight: bold;
      box-shadow: 0 2px 0 var(--nav-active-color);
    }
  }

  /* --- 漢堡按鈕與 RWD 邏輯 --- */
  #menu-toggle {
    display: none;
  }
  .navbar-toggler-custom {
    display: none;
    cursor: pointer;
    width: 30px;
    height: 24px;
    position: relative;
    z-index: 10;
    span {
      display: block;
      position: absolute;
      height: 3px;
      width: 100%;
      background: var(--gray-600);
      border-radius: 3px;
      opacity: 1;
      top: 50%;
      margin-top: -1.5px;
      transition: background 0.25s ease-in-out;
      &::before, &::after {
        content: '';
        display: block;
        position: absolute;
        height: 3px;
        width: 100%;
        background: var(--gray-600);
        border-radius: 3px;
        transition: transform 0.25s ease-in-out, top 0.25s ease-in-out;
      }

      &::before { top: -10px; }
      &::after { top: 10px; }
    }
  }
  @media (max-width: 992px) {
    .navbar-toggler-custom {
      display: block;
    }
    #navbarNav {
      display: none;
      width: 100%;
      margin-top: 1rem;
      border-top: 1px solid var(--gray-200);
      padding-top: 0.5rem;
      order: 3; 
      .navbar-nav {
        align-items: center;
      }
      .nav-item{
        display: block;
        width: 100%;
      }
      .nav-link {
        padding: 0.75rem 0;
        width: 100%;
        text-align: center;
        &:hover {
          background-color: color-mix(in srgb, var(--primary-color), white 90%);
          border-radius: var(--main-radius);
        }

        &.active {
          box-shadow: none;
          color: var(--primary-color);
        }
      }
    }
    .navbar:has(#menu-toggle:checked) {
      .navbar-toggler-custom span {
        background: transparent;
        &::before {
          top: 0;
          transform: rotate(45deg);
        }
        &::after {
          top: 0;
          transform: rotate(-45deg);
        }
      }
      #navbarNav {
        display: block;
        animation: slideDown 0.3s ease-out forwards;
      }
    }
  }
}

/* 簡單的下拉動畫 */
@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* bg-lazyload Utility Styles */
.bg-lazyload,
.bg-lazyloaded {
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.bg-position-top {
  background-position: top center;
}
.bg-position-bottom {
  background-position: bottom center;
}
.bg-position-left {
  background-position: center left;
}
.bg-position-right {
  background-position: center right;
}
.bg-position-center {
  background-position: center center;
}
.bg-position-top-left {
  background-position: top left;
}
.bg-position-top-right {
  background-position: top right;
}
.bg-position-bottom-left {
  background-position: bottom left;
}
.bg-position-bottom-right {
  background-position: bottom right;
}
.bg-fixed {
  background-attachment: fixed;
}

/* Footer Styles (Global) */
#footer {
  ul.footer-links {
    list-style: none;
    padding: 0;
    margin: 0 0 1rem 0;

    li {
      display: inline-block;
      margin: 0 10px;
    }

    a {
      text-decoration: none;
      color: #fff;

      &:hover {
        text-decoration: underline;
      }
    }
  }
}
#back-to-top {
  position: fixed;
  right: 1.2rem;
  bottom: 1.2rem;
  width: 2.5rem;
  height: 2.5rem;
  background-color: var(--primary-color);
  color: var(--gray-100);
  border-radius: 50%;
  text-decoration: none;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  box-shadow: 0 0 6px rgba(0,0,0,.8);
  z-index: 999;
  opacity: 0;
  translate: 0 20px;
  pointer-events: none;
  animation: fade-in linear forwards;
  animation-timeline: scroll();
  animation-range: 400px 500px;

  &:hover {
    box-shadow: 4px 4px 6px rgba(0,0,0,.8);
    transform: scale(1.1);
    transition: transform 0.2s, box-shadow 0.2s;
  }

  /* 簡單的箭頭圖示 */
  &::after {
    content: "▲";
    font-size: 1.2rem;
  }
}
@keyframes fade-in {
  to {
    opacity: 1;
    translate: 0 0;
    pointer-events: auto;
  }
}