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

:root {
    --color-bg: #fafafa;
    --color-surface: #ffffff;
    --color-text: #1a1a1a;
    --color-text-secondary: #6b7280;
    --color-accent: #2563eb;
    --color-accent-hover: #1d4ed8;
    --color-border: #e5e7eb;
    --color-tag-bg: #f3f4f6;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    --max-width: 1100px;
    --radius: 8px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

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

img {
    max-width: 100%;
    display: block;
}

/* ===== Navigation ===== */
.nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(250, 250, 250, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.nav__inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav__logo {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-text);
    letter-spacing: -0.02em;
}

.nav__links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav__links a {
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav__links a:hover,
.nav__links a.active {
    color: var(--color-text);
}

.nav__toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav__toggle span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--color-text);
    margin: 5px 0;
    transition: 0.3s;
}

/* ===== Hero Section ===== */
.hero {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 6rem 2rem 4rem;
}

.hero__greeting {
    font-size: 0.95rem;
    color: var(--color-accent);
    font-weight: 500;
    margin-bottom: 0.75rem;
    font-family: var(--font-mono);
}

.hero__title {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    font-weight: 700;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 1.25rem;
}

.hero__subtitle {
    font-size: 1.15rem;
    color: var(--color-text-secondary);
    max-width: 560px;
    line-height: 1.7;
    margin-bottom: 2rem;
}

.hero__cta {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--color-text);
    color: var(--color-bg);
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.95rem;
    transition: opacity 0.2s;
}

.hero__cta:hover {
    opacity: 0.85;
    color: var(--color-bg);
}

/* ===== Sections ===== */
.section {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 4rem 2rem;
}

.section__header {
    margin-bottom: 2.5rem;
}

.section__label {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-accent);
    margin-bottom: 0.5rem;
    font-family: var(--font-mono);
}

.section__title {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

/* ===== Projects Grid ===== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.project-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.75rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.project-card:hover {
    border-color: var(--color-accent);
    box-shadow: 0 4px 20px rgba(37, 99, 235, 0.08);
}

.project-card__tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.project-card__tag {
    font-size: 0.75rem;
    font-weight: 500;
    background: var(--color-tag-bg);
    color: var(--color-text-secondary);
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    font-family: var(--font-mono);
}

.project-card__title {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.project-card__desc {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.project-card__link {
    font-size: 0.85rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.project-card__link::after {
    content: '\2192';
    transition: transform 0.2s;
}

.project-card__link:hover::after {
    transform: translateX(3px);
}

/* ===== Education ===== */
.education-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.education-item {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.education-item__date {
    font-size: 0.8rem;
    font-family: var(--font-mono);
    color: var(--color-text-secondary);
    white-space: nowrap;
    min-width: 100px;
    padding-top: 0.15rem;
}

.education-item__content {
    flex: 1;
}

.education-item__degree {
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.education-item__school {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}

/* ===== Contact ===== */
.contact {
    text-align: center;
    padding: 5rem 2rem;
}

.contact__title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.contact__text {
    color: var(--color-text-secondary);
    margin-bottom: 2rem;
    max-width: 480px;
    margin-left: auto;
    margin-right: auto;
}

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

.contact__link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.65rem 1.25rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    color: var(--color-text);
    font-size: 0.9rem;
    font-weight: 500;
    transition: border-color 0.2s, background 0.2s;
}

.contact__link:hover {
    border-color: var(--color-accent);
    background: rgba(37, 99, 235, 0.04);
    color: var(--color-accent);
}

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

/* ===== Project Detail Page ===== */
.project-hero {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 5rem 2rem 3rem;
}

.project-hero__back {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    margin-bottom: 2rem;
}

.project-hero__back::before {
    content: '\2190';
}

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

.project-hero__title {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 1rem;
}

.project-hero__meta {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
}

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

.project-content {
    max-width: 720px;
    margin: 0 auto;
    padding: 0 2rem 5rem;
}

.project-content h2 {
    font-size: 1.35rem;
    font-weight: 600;
    margin: 2.5rem 0 1rem;
    letter-spacing: -0.01em;
}

.project-content p {
    color: var(--color-text-secondary);
    margin-bottom: 1.25rem;
    line-height: 1.75;
}

.project-content ul {
    margin-bottom: 1.25rem;
    padding-left: 1.25rem;
    color: var(--color-text-secondary);
}

.project-content li {
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

.project-links {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.project-links a {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.95rem;
}

.project-links--primary {
    background: var(--color-text);
    color: var(--color-bg);
}

.project-links--primary:hover {
    opacity: 0.85;
    color: var(--color-bg);
}

.project-links--secondary {
    border: 1px solid var(--color-border);
    color: var(--color-text);
}

.project-links--secondary:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .nav__links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-bg);
        flex-direction: column;
        padding: 1rem 2rem;
        gap: 1rem;
        border-bottom: 1px solid var(--color-border);
    }

    .nav__links.open {
        display: flex;
    }

    .nav__toggle {
        display: block;
    }

    .hero {
        padding: 4rem 1.5rem 3rem;
    }

    .section {
        padding: 3rem 1.5rem;
    }

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

    .education-item {
        flex-direction: column;
        gap: 0.25rem;
    }

    .education-item__date {
        min-width: unset;
    }

    .project-hero {
        padding: 4rem 1.5rem 2rem;
    }

    .project-content {
        padding: 0 1.5rem 4rem;
    }

    .project-links {
        flex-direction: column;
    }
}