:root {
    /* 基礎色調 - OKLCH 轉換為 HEX 近似值以兼容舊瀏覽器，主要使用 CSS 變數 */
    --background: #0f111a; /* oklch(0.12 0.01 260) */
    --foreground: #ffffff; /* 純白文字 */
    
    /* 品牌色 */
    --brand-blue: #4a88ee; /* oklch(0.65 0.18 250) */
    --brand-purple: #a855f7; /* oklch(0.65 0.20 290) */
    --brand-teal: #2dd4bf; /* oklch(0.75 0.15 180) */
    --brand-gold: #fbbf24; /* oklch(0.85 0.15 85) */
    
    --card-bg: rgba(255, 255, 255, 0.05);
    --card-border: rgba(255, 255, 255, 0.1);
    --text-muted: #e5e7eb; /* 淺灰色 (接近白) */
}

body {
    background-color: var(--background);
    color: var(--foreground);
    font-family: 'Noto Sans TC', sans-serif;
    line-height: 1.8; /* 增加行高以提升閱讀性 */
    overflow-x: hidden;
    background-image: 
        radial-gradient(circle at 15% 50%, rgba(74, 136, 238, 0.15), transparent 25%),
        radial-gradient(circle at 85% 30%, rgba(168, 85, 247, 0.15), transparent 25%);
    background-attachment: fixed;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Noto Serif TC', serif;
    font-weight: 700;
    color: #ffffff;
}

p, li, span, div {
    color: #ffffff;
}

.text-muted {
    color: var(--text-muted) !important;
}

.font-mono {
    font-family: 'JetBrains Mono', monospace;
}

/* 導航列 */
.navbar {
    background: rgba(15, 17, 26, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--card-border);
    padding: 1rem 0;
}

.navbar-brand {
    font-family: 'Noto Serif TC', serif;
    font-weight: 900;
    color: var(--foreground) !important;
    font-size: 1.5rem;
}

.nav-link {
    color: var(--text-muted) !important;
    font-weight: 500;
    transition: color 0.3s;
    font-size: 1.1rem;
    margin: 0 0.5rem;
}

.nav-link:hover, .nav-link.active {
    color: var(--brand-blue) !important;
}

/* 按鈕 */
.btn-brand {
    background-color: var(--brand-blue);
    color: white !important;
    border-radius: 50px;
    padding: 0.75rem 2rem;
    font-weight: 500;
    border: none;
    transition: all 0.3s;
    box-shadow: 0 0 20px rgba(74, 136, 238, 0.3);
}

.btn-brand:hover {
    background-color: #3b82f6;
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(74, 136, 238, 0.5);
}

.btn-outline-brand {
    background-color: transparent;
    color: var(--foreground) !important;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    padding: 0.75rem 2rem;
    font-weight: 500;
    transition: all 0.3s;
}

.btn-outline-brand:hover {
    background-color: rgba(255, 255, 255, 0.05);
    border-color: var(--foreground);
    transform: translateY(-2px);
}

/* 玻璃擬態卡片 */
.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--card-border);
    border-radius: 1.5rem;
    transition: all 0.3s ease;
}

.glass-card:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(74, 136, 238, 0.3);
    box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
    transform: translateY(-5px);
}

/* 文字漸層 */
.text-gradient-brand {
    background: linear-gradient(to right, var(--brand-blue), var(--brand-purple), var(--brand-teal));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.text-gradient-gold {
    background: linear-gradient(to right, var(--brand-gold), #fdba74, var(--brand-gold));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 區塊間距 */
section {
    padding: 6rem 0;
}

/* 頁面標題區塊 */
.page-header {
    padding: 8rem 0 4rem;
    text-align: center;
    background: radial-gradient(circle at center, rgba(74, 136, 238, 0.1) 0%, transparent 70%);
}

/* 圖片樣式 */
.img-rounded-shadow {
    border-radius: 1rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    border: 1px solid rgba(255,255,255,0.1);
    transition: transform 0.3s;
}

.img-rounded-shadow:hover {
    transform: scale(1.02);
}

/* Utility Classes */
.text-brand-blue { color: var(--brand-blue) !important; }
.text-brand-purple { color: var(--brand-purple) !important; }
.text-brand-teal { color: var(--brand-teal) !important; }
.text-brand-gold { color: var(--brand-gold) !important; }

.bg-brand-blue-soft { background-color: rgba(74, 136, 238, 0.1); }
.bg-brand-purple-soft { background-color: rgba(168, 85, 247, 0.1); }
.bg-brand-teal-soft { background-color: rgba(45, 212, 191, 0.1); }
.bg-brand-gold-soft { background-color: rgba(251, 191, 36, 0.1); }

.badge-module {
    display: inline-block;
    padding: 0.5rem 1.5rem;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    margin-bottom: 1.5rem;
    border: 1px solid;
}

/* Footer */
footer {
    background: rgba(15, 17, 26, 0.95);
    border-top: 1px solid var(--card-border);
    padding: 3rem 0;
    margin-top: auto;
}