:root {
    --bg-color: #0d1117;
    --card-bg: #161b22;
    --card-hover-bg: #1f2428;
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent-color: #58a6ff;
    --accent-hover: #79c0ff;
    --border-color: #30363d;
    --tag-bg: #21262d;
    --tag-text: #8b949e;
    --font-mono: 'JetBrains Mono', monospace;
    --font-sans: 'Noto Sans TC', sans-serif;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.3);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-sans);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    padding: 3rem 1.5rem;
}

.container {
    max-width: 900px;
    width: 100%;
    animation: fadeIn 0.8s ease-out;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 4rem;
}

.avatar-placeholder {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, #238636, #2ea043);
    border-radius: 50%;
    margin: 0 auto 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-mono);
    font-size: 3rem;
    font-weight: bold;
    color: white;
    box-shadow: 0 0 30px rgba(46, 160, 67, 0.3);
    border: 4px solid var(--bg-color);
}

h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(to right, var(--accent-color), #bc8cff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.05rem;
}

.tagline {
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 1rem;
    margin-bottom: 1.5rem;
}

.header-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

.social-link {
    color: var(--text-secondary);
    font-size: 1.5rem;
    transition: all 0.2s ease;
}

.social-link:hover {
    color: var(--accent-color);
    transform: translateY(-2px);
}

/* Layout */
.section {
    margin-bottom: 4rem;
}

h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

h2 i {
    color: var(--accent-color);
    font-size: 1.2rem;
}

/* Cards (Generic) */
.card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-sm);
}

/* About Section */
.about-section .card {
    border-left: 4px solid var(--accent-color);
}

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.project-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    position: relative;
    overflow: hidden;
}

.project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-color), #bc8cff);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--text-secondary);
    background-color: var(--card-hover-bg);
}

.project-card:hover::before {
    opacity: 1;
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.project-header h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
}

.project-link {
    color: var(--text-secondary);
    font-size: 1rem;
    transition: color 0.2s;
}

.project-link:hover {
    color: var(--accent-color);
}

.project-desc {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

/* Tech Stack & Tags */
.tech-stack, .skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tech-tag, .skill-tag {
    background-color: var(--tag-bg);
    color: var(--tag-text);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    border: 1px solid transparent;
    transition: all 0.2s ease;
}

.project-card:hover .tech-tag,
.skill-category:hover .skill-tag {
    border-color: var(--accent-color);
    color: var(--accent-color);
    background-color: rgba(88, 166, 255, 0.1);
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.skill-category h3 {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

/* Footer */
footer {
    margin-top: 5rem;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    padding-top: 2rem;
}

footer a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s;
}

footer a:hover {
    text-decoration: underline;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Responsive */
@media (max-width: 768px) {
    body {
        padding: 2rem 1rem;
    }
    
    h1 {
        font-size: 2.5rem;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: 1fr;
    }
    
    .header-links {
        gap: 2rem;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 2rem;
    }
    
    .avatar-placeholder {
        width: 100px;
        height: 100px;
        font-size: 2.5rem;
    }
}