:root {
    --pulp-white: #F9F9F9;
    --ink-blue: #1A237E;
    --lignin-grey: #BDBDBD;
    --eco-green: #43A047;
    --text-dark: #212121;
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

body {
    background-color: var(--pulp-white);
    color: var(--text-dark);
    font-family: var(--font-main);
    line-height: 1.6;
    overflow-x: hidden;
}

/* 纖維紋理背景 */
.fiber-texture {
    background-image: url('https://www.transparenttextures.com/patterns/paper-fibers.png');
}

.navbar {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--lignin-grey);
    padding: 1rem 2rem;
}

.navbar-brand {
    font-weight: 800;
    color: var(--ink-blue) !important;
    letter-spacing: -0.5px;
}

.nav-link {
    color: var(--text-dark) !important;
    font-weight: 500;
    margin: 0 10px;
    transition: color 0.3s ease;
}

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

.btn-primary {
    background-color: var(--ink-blue);
    border-color: var(--ink-blue);
}

.btn-primary:hover {
    background-color: #0D145A;
    border-color: #0D145A;
}

.section-title {
    color: var(--ink-blue);
    font-weight: 700;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 50px;
    height: 3px;
    background-color: var(--eco-green);
}

.mono-text {
    font-family: var(--font-mono);
    font-size: 0.9rem;
}

footer {
    background-color: var(--ink-blue);
    color: white;
    padding: 4rem 0 2rem;
}

.footer-link {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-link:hover {
    color: white;
}

/* 疊層感卡片 */
.layered-card {
    background: white;
    border: 1px solid rgba(0,0,0,0.05);
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border-radius: 0;
}

.layered-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.1);
}