/* ----- 核心變數與基礎設定 ----- */
:root{--glow-primary: #00d4ff;--bg-card: #131322;}
:root { --bg-dark: #0a0a1a; --bg-darker:#050510; --text-primary: #ffffff; --text-secondary: #a0a0c0; --border-color: #2a2a4a; --glow-primary: #00d4ff; --glow-secondary: #00ff88; --gradient-primary: linear-gradient(135deg, #00d4ff, #00ff88); --transition-fast: 0.2s ease; --transition-normal: 0.3s ease; --bg-tab-active: var(--glow-primary); --bg-tab-hover: rgba(0, 212, 255, 0.1); --bg-tab-default: rgba(255, 255, 255, 0.05); --info-color: #17a2b8; --danger-color: #dc3545; --border-color2: #478d84; }
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: 'Noto Sans TC', 'Microsoft JhengHei', sans-serif; line-height: 1.6; overflow-x: hidden; }
a { color: var(--glow-primary); text-decoration: none; transition: var(--transition-fast); }
a:hover { color: var(--glow-secondary); }
::selection { background: var(--glow-primary); color: var(--bg-dark); }

/* 高級自訂頁簽不斷線法 STAR */
.nav-tabs-custom { border-bottom: none !important; display: flex; gap: 5px; position: relative; padding-bottom: 0; }
.nav-tabs-custom::after { content: ''; position: absolute; bottom: -2px; left: 0; right: 0; height: 2px; background: var(--glow-primary); z-index: 1; pointer-events: none; }
.nav-tabs-custom .nav-link { color: var(--text-secondary); border: 1px solid var(--border-color2) !important; border-bottom: none !important; background: var(--bg-tab-default); padding: 0.75rem 1.5rem; transition: var(--transition-fast); border-radius: 8px 8px 0 0; position: relative; z-index: 2; margin-bottom: 0; }
.nav-tabs-custom .nav-link:hover { color: var(--glow-primary); background: var(--bg-tab-hover); border-color: var(--glow-primary) !important; }
.nav-tabs-custom .nav-link.active { color: var(--bg-dark); background: var(--bg-tab-active); border-color: var(--glow-primary) !important; font-weight: bold; box-shadow: 0 -5px 15px rgba(0, 212, 255, 0.3); }
.fa-1_5x { font-size: 1.5rem; }

/* ----- 導航列 ----- */
#mainNav { background: linear-gradient(180deg, rgba(10, 10, 26, 0.95), rgba(10, 10, 26, 0.8)); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border-color); padding: 0.8rem 0; transition: var(--transition-normal); }
#mainNav.nav-scrolled { background: rgba(10, 10, 26, 0.98); }
#mainNav .navbar-brand { font-size: 1.5rem; font-weight: bold; color: var(--text-primary) !important; text-shadow: 0 0 10px var(--glow-primary); }
#mainNav .nav-link { color: var(--text-secondary) !important; padding: 0.5rem 1rem !important; position: relative; transition: var(--transition-fast); }
#mainNav .nav-link:hover, #mainNav .nav-link.active { color: var(--glow-primary) !important; }
#mainNav .nav-link::after { content: ''; position: absolute; bottom: 0; left: 50%; width: 0; height: 2px; background: var(--gradient-primary); transition: var(--transition-normal); transform: translateX(-50%); }
#mainNav .nav-link:hover::after { width: 80%; }
.navbar-toggler { border-color: var(--glow-primary); }
.navbar-toggler-icon { filter: invert(1); }
.navbar-toggler-icon-custom { color: #ffc107; font-size: 1.5rem; }

/* ----- 區塊通用樣式 ----- */
.section-padding { padding: 10px 0 10px; }
.section-alt { background: var(--bg-darker); }
.section-top { padding: 83px 0 0px }
.section-title i { margin-right: 0.5rem; color: var(--glow-primary); }
.section-title::after { content: ''; position: absolute; bottom: 0; left: 50%; transform: translateX(-50%); width: 160px; height: 4px; background: linear-gradient(90deg, var(--danger-color), var(--info-color)); border-radius: 2px; }
.collapse-trigger { cursor: pointer; display: flex; align-items: center; justify-content: center; }
.collapse-trigger .arrow-icon { transition: transform 0.3s ease; font-size: 1.5rem; color: var(--glow-primary); margin-left: 1rem; }
.collapse-trigger:not(.collapsed) .arrow-icon { transform: rotate(180deg); }
.collapse-trigger:hover { filter: brightness(1.2); }


.section-title { text-align: center; font-size: 2.5rem; font-weight: bold; margin-bottom: 3rem;  text-shadow: 0 0 20px var(--glow-primary); position: relative; padding-bottom: 20px;color:var(--border-color); }


.section-top { border-bottom: 2px solid var(--color-border); box-shadow: var(--shadow-sm); transition: var(--transition-base); }


/* ----- 回到頂端按鈕相關樣式 ----- */
.floating-buttons { position: fixed; bottom: 80px; right: 2rem; display: flex; flex-direction: column; gap: 1rem; z-index: 1000; }
.btn-floating { width: 50px; height: 50px; border-radius: 50%; border: none; display: flex; align-items: center; justify-content: center; font-size: 1.25rem; cursor: pointer; transition: var(--transition-smooth); box-shadow: var(--shadow-lg); }
.btn-scroll-top { background: var(--gold-gradient); color: var(--color-white); opacity: 0; visibility: hidden; transform: translateY(20px); }
.btn-scroll-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.btn-scroll-top:hover { transform: translateY(-3px); box-shadow: var(--shadow-gold); }