:root {
    --color-rock-black: #1B1B1B;
    --color-hydraulic-yellow: #FFD600;
    --color-lining-gray: #B0BEC5;
    --color-laser-blue: #00B0FF;
    --color-text-light: #F5F5F5;
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;
}

body {
    background-color: var(--color-rock-black);
    color: var(--color-text-light);
    font-family: var(--font-main);
    overflow-x: hidden;
}

/* 重型工業風格標題 */
h1, h2, h3, h4, h5, h6 {
    text-transform: uppercase;
    font-weight: 800;
    letter-spacing: 2px;
    border-left: 5px solid var(--color-hydraulic-yellow);
    padding-left: 15px;
    margin-bottom: 1.5rem;
}

.navbar {
    background-color: rgba(27, 27, 27, 0.95);
    border-bottom: 2px solid var(--color-hydraulic-yellow);
    padding: 1rem 0;
}

.navbar-brand {
    font-weight: 900;
    color: var(--color-hydraulic-yellow) !important;
    letter-spacing: 1px;
}

.nav-link {
    color: var(--color-lining-gray) !important;
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.9rem;
    margin: 0 10px;
    transition: color 0.3s;
}

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

/* 按鈕樣式 */
.btn-industrial {
    background-color: var(--color-hydraulic-yellow);
    color: var(--color-rock-black);
    border-radius: 0;
    font-weight: 800;
    text-transform: uppercase;
    padding: 12px 30px;
    border: none;
    transition: all 0.3s;
}

.btn-industrial:hover {
    background-color: #e6c100;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(255, 214, 0, 0.3);
}

/* 頁尾 */
footer {
    background-color: #111;
    border-top: 1px solid #333;
    padding: 60px 0 30px;
    margin-top: 100px;
}

.footer-brand {
    color: var(--color-hydraulic-yellow);
    font-size: 1.5rem;
    font-weight: 900;
    margin-bottom: 20px;
}

.footer-link {
    color: var(--color-lining-gray);
    text-decoration: none;
    display: block;
    margin-bottom: 10px;
}

.footer-link:hover {
    color: var(--color-hydraulic-yellow);
}

/* 技術數據卡片 */
.tech-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid #333;
    padding: 30px;
    height: 100%;
    transition: border-color 0.3s;
}

.tech-card:hover {
    border-color: var(--color-hydraulic-yellow);
}

.tech-value {
    font-family: var(--font-mono);
    font-size: 2.5rem;
    color: var(--color-hydraulic-yellow);
    margin-bottom: 5px;
}

.tech-label {
    color: var(--color-lining-gray);
    font-size: 0.8rem;
    text-transform: uppercase;
}

/* 動畫效果 */
@keyframes rotate-cutter {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.tbm-cutter-head {
    animation: rotate-cutter 20s linear infinite;
}