/* ---------- 全局 ---------- */
html, body {
  height: 100%;
  margin: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  transition: background-color 0.3s, color 0.3s;
}

/* 連結樣式 */
a { 
  text-decoration: none;
}

/* ---------- 主題 ---------- */
html.light-theme {
  --background-color: #f5f7fa;
  --text-color: #222;
  --navbar-bg: linear-gradient(90deg, #4ca1af, #3a8dde);
  --navbar-link-color: #fff;
  --footer-bg: #4ca1af;
  --footer-border-color: #ff9800;
}

html.dark-theme {
  --background-color: #121212;
  --text-color: #f0f0f0;
  --navbar-bg: linear-gradient(90deg, #1f1f1f, #333333);
  --navbar-link-color: #f0f0f0;
  --footer-bg: #1f1f1f;
  --footer-border-color: #ff9800;
}

/* ---------- 主題背景與文字顏色 ---------- */
body {
  background-color: var(--background-color);
  color: var(--text-color);
}

/* Navbar 背景與連結顏色 */
.navbar {
  background: var(--navbar-bg);
  color: var(--navbar-link-color);
  transition: background-color 0.3s, color 0.3s;
}

.navbar-links a {
  color: var(--navbar-link-color);
  transition: background-color 0.3s;
}

.navbar-links a:hover {
  background-color: rgba(255, 255, 255, 0.2);
}

/* Footer 背景與顏色 */
footer {
  background-color: var(--footer-bg);
  color: var(--text-color);
  border-top: 3px solid var(--footer-border-color);
  transition: background-color 0.3s, color 0.3s;
}

/* ---------- Navbar ---------- */
.navbar {
  padding: 12px 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: fixed;
  top: 0;
  width: 100%;
  height: 70px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
  z-index: 999;
}

.navbar-logo span {
  font-size: 1.6rem;
  font-weight: bold;
  letter-spacing: 1px;
}

/* ---------- Navbar 選項桌面版 ---------- */
.navbar-links {
  display: flex;
  align-items: center;
}

.navbar-links a {
  display: inline-block;
  width: 100px; /* 統一寬度 */
  text-align: center;
  margin-left: 15px;
  font-weight: 500;
  padding: 6px 0;
  border-radius: 6px;
  transition: background-color 0.3s;
}

.navbar-links a:hover { 
  background-color: rgba(255, 255, 255, 0.2);
}

/* ---------- Main ---------- */
main {
  flex: 1 0 auto;
  padding: 100px 20px 40px;
}

.card {
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  transition: transform 0.2s, box-shadow 0.3s;
  background-color: #fff;
  color: var(--text-color);
}

html.dark-theme .card {
  background-color: #1e1e1e;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

/* ---------- Footer ---------- */
footer {
  text-align: center;
  padding: 25px;
  flex-shrink: 0;
  border-top: 3px solid var(--footer-border-color);
  transition: background 0.3s, color 0.3s;
}

/* ---------- 浮動主題切換按鈕 ---------- */
.theme-toggle {
  position: fixed;
  bottom: 25px;
  right: 25px;
  width: 45px;
  height: 45px;
  border-radius: 50%;
  border: none;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #888;
  color: #fff;
  box-shadow: 0 5px 12px rgba(0, 0, 0, 0.3);
  transition: transform 0.2s, box-shadow 0.3s, background 0.3s;
  z-index: 1000;
}

.theme-toggle:hover {
  transform: translateY(-2px) scale(1.05);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.4);
}

/* ---------- 手機抽屜 Navbar ---------- */
.menu-toggle {
  display: none; /* 桌面版隱藏 */
  font-size: 24px;
  cursor: pointer;
  color: #fff;
}

@media (max-width: 768px) {
  .menu-toggle { display: block; }

  /* 隱藏桌面版 flex 排列 */
  .navbar-links { display: none; }

  .navbar-links.mobile {
    display: flex;
    position: fixed;
    top: 70px;
    left: 0;
    width: 100%;
    max-height: 0;
    overflow: hidden;
    background-color: rgba(58, 141, 222, 0.95);
    flex-direction: column;
    align-items: center;
    padding: 0;
    border-radius: 0 0 12px 12px; /* 圓角 */
    transition: max-height 0.3s ease, padding 0.3s ease;
    z-index: 998;
  }

  html.dark-theme .navbar-links.mobile {
    background-color: rgba(31, 31, 31, 0.95);
  }

  .navbar-links.mobile.show {
    max-height: 500px;
    padding: 20px 0;
  }

  .navbar-links.mobile a {
    display: block;
    width: 100%;
    text-align: center;
    margin: 8px 0;
    font-size: 1.2rem;
    padding: 12px 0;
    color: inherit;
    transition: background-color 0.3s;
  }

  .navbar-links.mobile a:hover {
    background-color: rgba(255, 255, 255, 0.2);
  }
}