/* 
 * Yi Shen - Personal Portfolio
 * Premium Dark Theme with Glassmorphism
 */

:root {
    /* Color Palette */
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --surface-glass: rgba(30, 41, 59, 0.7);
    --primary-color: #38bdf8;
    --secondary-color: #818cf8;
    --accent-color: #22d3ee;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent-glow: rgba(56, 189, 248, 0.3);

    /* Typography */
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;

    /* Spacing */
    --container-width: 1100px;
    --section-spacing: 100px;
}

/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-main);
    line-height: 1.7;
    overflow-x: hidden;
}

/* Typography */
h1,
h2,
h3,
h4 {
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
}

h1 {
    font-size: 4rem;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color), var(--accent-color));
    background-size: 200% 200%;
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: gradientShift 5s ease infinite;
}

@keyframes gradientShift {

    0%,
    100% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }
}

h2 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 60px;
    height: 4px;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: all 0.3s ease;
}

a:hover {
    color: var(--secondary-color);
}

/* Layout */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    padding: var(--section-spacing) 0;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    padding: 1rem 0;
}

.nav-container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-menu a {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-menu a:hover {
    color: var(--text-primary);
}

.nav-cta {
    background: var(--primary-color);
    color: var(--bg-color) !important;
    padding: 0.5rem 1.25rem;
    border-radius: 20px;
    font-weight: 600;
}

.nav-cta:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

/* Hero Section */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 80px;
    position: relative;
    overflow: hidden;
}

#hero::before {
    content: '';
    position: absolute;
    top: 20%;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin: 1rem 0 2rem;
    font-weight: 400;
}

.hero-description {
    max-width: 650px;
    margin: 0 auto 2.5rem;
    font-size: 1.15rem;
    color: var(--text-secondary);
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    padding: 14px 32px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s ease;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary-color);
    color: var(--bg-color);
}

.btn-primary:hover {
    background: var(--secondary-color);
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(56, 189, 248, 0.3);
}

.btn-outline {
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    background: transparent;
}

.btn-outline:hover {
    background: var(--primary-color);
    color: var(--bg-color);
    transform: translateY(-3px);
}

/* Glassmorphism Card */
.glass-card {
    background: var(--surface-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 16px;
    padding: 2rem;
    transition: all 0.3s ease;
}

.glass-card:hover {
    transform: translateY(-5px);
    border-color: rgba(56, 189, 248, 0.3);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* About Section */
.about-text {
    font-size: 1.15rem;
    color: var(--text-primary);
}

.about-text strong {
    color: var(--primary-color);
}

/* Experience Section */
.experience-card {
    margin-bottom: 2rem;
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    margin-bottom: 1.25rem;
    gap: 1rem;
}

.experience-title {
    color: var(--primary-color);
    font-size: 1.4rem;
    margin-bottom: 0.25rem;
}

.experience-company {
    font-weight: 400;
    color: var(--text-primary);
    font-size: 1.1rem;
}

.experience-date {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.experience-list {
    list-style: none;
    padding-left: 0;
}

.experience-list li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.experience-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

.experience-list li strong {
    color: var(--text-primary);
}

/* Homelab Section */
#homelab {
    background: linear-gradient(180deg, transparent 0%, rgba(56, 189, 248, 0.03) 50%, transparent 100%);
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.15rem;
    margin-bottom: 3rem;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.5rem;
}

.project-card {
    padding: 1.75rem;
}

.project-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.project-title {
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.project-description {
    font-size: 0.95rem;
    margin-bottom: 1.25rem;
    color: var(--text-secondary);
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    background: rgba(56, 189, 248, 0.1);
    color: var(--primary-color);
    padding: 0.35rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid rgba(56, 189, 248, 0.2);
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
}

.skill-card {
    padding: 1.5rem;
    text-align: center;
}

.skill-title {
    font-size: 1.1rem;
    margin-bottom: 0.75rem;
    color: var(--secondary-color);
}

.skill-card p {
    margin-bottom: 0;
    font-size: 0.95rem;
}

/* Education Section */
.education-card {
    margin-bottom: 1.5rem;
}

.education-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.education-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 0.75rem;
}

/* Footer */
footer {
    padding: 4rem 0;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

footer h2 {
    margin-bottom: 2rem;
}

footer h2::after {
    left: 50%;
    transform: translateX(-50%);
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: 2.5rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.contact-links a {
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.copyright {
    font-size: 0.9rem;
    opacity: 0.5;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fade-in {
    animation: fadeIn 0.8s ease-out forwards;
}

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

    h2 {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    :root {
        --section-spacing: 60px;
    }

    .nav-menu {
        display: none;
        /* Would need JS for mobile menu */
    }

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

    .contact-links {
        flex-direction: column;
        gap: 1rem;
    }

    .experience-header {
        flex-direction: column;
    }
}