/* ═══════════════════════════════════════════════════════
   RYAN SHAY — Portfolio
   Dark theme, professional-casual, subtle terminal touches
   ═══════════════════════════════════════════════════════ */

/* ── Foundations ── */
:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-elevated: #1c2333;
    --bg-hover: #21262d;

    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #484f58;

    --accent-blue: #4d94ff;
    --accent-green: #00d68f;
    --accent-purple: #7c3aed;
    --accent-cyan: #22d3ee;

    --border-default: #30363d;
    --border-muted: #21262d;

    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", Menlo, Consolas, monospace;

    --max-width: 1100px;
    --section-padding: 6rem 0;
    --border-radius: 10px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

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

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

::selection {
    background: var(--accent-blue);
    color: var(--bg-primary);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}


/* ── Navigation ── */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(13, 17, 23, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.nav.scrolled {
    border-bottom-color: var(--border-default);
    box-shadow: 0 1px 12px rgba(0, 0, 0, 0.4);
}

.nav-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.05rem;
    text-decoration: none;
}

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

.nav-brand-icon {
    font-family: var(--font-mono);
    color: var(--accent-green);
    font-size: 0.9rem;
    background: var(--bg-secondary);
    padding: 0.2rem 0.5rem;
    border-radius: 6px;
    border: 1px solid var(--border-default);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.25rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    text-decoration: none;
    position: relative;
    transition: color var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-blue);
    transition: width var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}


/* ── Hero ── */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    padding: 6rem 1.5rem 4rem;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(77, 148, 255, 0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(124, 58, 237, 0.06) 0%, transparent 50%),
        var(--bg-primary);
}

.hero-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.hero-avatar {
    position: relative;
    width: 140px;
    height: 140px;
    margin-bottom: 0.5rem;
}

.hero-avatar-ring {
    position: absolute;
    inset: -4px;
    border-radius: 50%;
    background: conic-gradient(
        from 0deg,
        var(--accent-blue),
        var(--accent-purple),
        var(--accent-green),
        var(--accent-cyan),
        var(--accent-blue)
    );
    animation: avatarSpin 8s linear infinite;
    opacity: 0.7;
}

@keyframes avatarSpin {
    to { transform: rotate(360deg); }
}

.hero-avatar-inner {
    position: absolute;
    inset: 3px;
    border-radius: 50%;
    background: var(--bg-primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-avatar-icon {
    font-family: var(--font-mono);
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--accent-green);
    letter-spacing: -2px;
}

.hero-name {
    font-size: 3.2rem;
    font-weight: 700;
    letter-spacing: -1px;
    line-height: 1.1;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-title {
    font-size: 1.2rem;
    color: var(--accent-blue);
    font-weight: 500;
    letter-spacing: 0.5px;
}

.hero-tagline {
    font-family: var(--font-mono);
    font-size: 1rem;
    color: var(--text-secondary);
    min-height: 1.7em;
}

.hero-cursor {
    animation: blink 1s step-end infinite;
    color: var(--accent-green);
}

@keyframes blink {
    50% { opacity: 0; }
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1rem;
    padding: 0.75rem 1.75rem;
    background: var(--bg-secondary);
    color: var(--accent-blue);
    border: 1px solid var(--border-default);
    border-radius: 8px;
    font-weight: 500;
    font-size: 0.95rem;
    text-decoration: none;
    transition: all var(--transition);
}

.hero-cta:hover {
    background: var(--bg-elevated);
    border-color: var(--accent-blue);
    color: var(--accent-blue);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(77, 148, 255, 0.15);
}

.hero-cta i {
    transition: transform var(--transition);
}

.hero-cta:hover i {
    transform: translateY(3px);
}

.hero-scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
}

.hero-scroll-line {
    width: 1px;
    height: 48px;
    background: linear-gradient(to bottom, var(--accent-blue), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(0.6); }
    50% { opacity: 1; transform: scaleY(1); }
}


/* ── Sections (shared) ── */
.section {
    padding: var(--section-padding);
}

.section-heading {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 2.5rem;
    letter-spacing: -0.5px;
}

.section-heading-accent {
    font-family: var(--font-mono);
    color: var(--accent-green);
    margin-right: 0.4rem;
    font-weight: 400;
}


/* ── About ── */
.about-content {
    max-width: 750px;
}

.about-content p {
    margin-bottom: 1.3rem;
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.8;
}

.about-intro {
    font-size: 1.2rem !important;
    color: var(--text-primary) !important;
    font-weight: 400;
}


/* ── Stats ── */
.stats {
    padding: 4rem 0;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-default);
    border-bottom: 1px solid var(--border-default);
}

.stats-grid {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    text-align: center;
}

.stat-number {
    font-size: 2.8rem;
    font-weight: 700;
    color: var(--accent-blue);
    font-variant-numeric: tabular-nums;
    line-height: 1.2;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 0.3rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 500;
}


/* ── Projects ── */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.project-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-default);
    border-radius: var(--border-radius);
    overflow: hidden;
    display: flex;
    transition: all var(--transition);
}

.project-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3), 0 0 0 1px rgba(77, 148, 255, 0.1);
}

.project-card-accent {
    width: 4px;
    flex-shrink: 0;
    background: linear-gradient(to bottom, var(--accent-blue), var(--accent-purple));
    transition: width var(--transition);
}

.project-card:hover .project-card-accent {
    width: 5px;
}

.project-card[data-category="enterprise"] .project-card-accent {
    background: linear-gradient(to bottom, var(--accent-blue), var(--accent-cyan));
}

.project-card[data-category="creative"] .project-card-accent {
    background: linear-gradient(to bottom, var(--accent-purple), #ec4899);
}

.project-card[data-category="ai"] .project-card-accent {
    background: linear-gradient(to bottom, var(--accent-green), var(--accent-cyan));
}

.project-card[data-category="tool"] .project-card-accent {
    background: linear-gradient(to bottom, var(--accent-cyan), var(--accent-blue));
}

.project-card[data-category="historical"] .project-card-accent {
    background: linear-gradient(to bottom, var(--text-muted), var(--text-secondary));
}

.project-card-body {
    padding: 1.5rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.project-card-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1rem;
}

.project-card-icon {
    font-size: 1.6rem;
    color: var(--accent-blue);
    margin-top: 0.15rem;
    flex-shrink: 0;
}

.project-card[data-category="creative"] .project-card-icon { color: var(--accent-purple); }
.project-card[data-category="ai"] .project-card-icon { color: var(--accent-green); }
.project-card[data-category="tool"] .project-card-icon { color: var(--accent-cyan); }
.project-card[data-category="historical"] .project-card-icon { color: var(--text-secondary); }

.project-card-title {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 0.15rem;
    line-height: 1.3;
}

.project-card-subtitle {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 500;
}

.project-card-desc {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.65;
    flex: 1;
    margin-bottom: 1rem;
}

.project-card-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 0.75rem;
}

.tech-pill {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    font-size: 0.72rem;
    font-family: var(--font-mono);
    background: var(--bg-hover);
    color: var(--text-secondary);
    border-radius: 4px;
    border: 1px solid var(--border-muted);
    white-space: nowrap;
}

.project-card-link {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--accent-blue);
    text-decoration: none;
    margin-top: auto;
}

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

.project-card-link i {
    font-size: 0.8rem;
    transition: transform var(--transition);
}

.project-card-link:hover i {
    transform: translate(2px, -2px);
}


/* ── Skills ── */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.skill-group {
    background: var(--bg-secondary);
    border: 1px solid var(--border-default);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    transition: border-color var(--transition);
}

.skill-group:hover {
    border-color: rgba(77, 148, 255, 0.3);
}

.skill-group-header {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.skill-group-header i {
    color: var(--accent-blue);
    font-size: 1.1rem;
}

.skill-group-header h3 {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.skill-group-items {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.skill-pill {
    display: inline-block;
    padding: 0.3rem 0.7rem;
    font-size: 0.82rem;
    background: var(--bg-hover);
    color: var(--text-secondary);
    border-radius: 6px;
    border: 1px solid var(--border-muted);
    transition: all var(--transition);
}

.skill-pill:hover {
    color: var(--text-primary);
    border-color: var(--accent-blue);
    background: rgba(77, 148, 255, 0.08);
}


/* ── Papers Section ── */
.papers {
    background:
        radial-gradient(ellipse at 30% 0%, rgba(77, 148, 255, 0.04) 0%, transparent 60%),
        var(--bg-primary);
}

.papers-category {
    margin-bottom: 2rem;
}

.papers-category-title {
    font-size: 1rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.papers-category-title i {
    color: var(--accent-green);
}

.papers-disclaimer {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    margin: -0.75rem 0 1.5rem 0;
    line-height: 1.5;
}

.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 1.25rem;
}

.paper-card {
    position: relative;
    background: var(--bg-secondary);
    border: 1px solid var(--border-default);
    border-radius: var(--border-radius);
    overflow: hidden;
    text-decoration: none;
    color: inherit;
    transition: border-color 0.2s ease, transform 0.2s ease;
    display: block;
}

.paper-card:hover {
    border-color: var(--accent-green);
    transform: translateY(-2px);
}

.paper-card-accent {
    height: 3px;
    background: linear-gradient(90deg, var(--accent-green), var(--accent-blue));
}

.paper-card-body {
    padding: 1.5rem;
}

.paper-card-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0 0 0.75rem 0;
    line-height: 1.4;
}

.paper-card-excerpt {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0 0 1rem 0;
}

.paper-card-link {
    font-size: 0.8rem;
    color: var(--accent-green);
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.paper-card:hover .paper-card-link {
    gap: 0.6rem;
}

/* ── Paper Article Page ── */
.paper-article {
    padding-top: 6rem;
    padding-bottom: 4rem;
    min-height: 80vh;
}

.paper-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.paper-back {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    transition: color 0.2s ease;
}

.paper-back:hover {
    color: var(--accent-green);
}

.paper-category-tag {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--accent-green);
    background: rgba(0, 214, 143, 0.1);
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    font-weight: 500;
}

.paper-content {
    max-width: 720px;
}

.paper-content h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
    margin: 0 0 2rem 0;
}

.paper-content h2 {
    font-size: 1.35rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 2.5rem 0 1rem 0;
    padding-top: 0.5rem;
}

.paper-content h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 2rem 0 0.75rem 0;
}

.paper-content p {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 0 0 1.25rem 0;
}

.paper-content strong {
    color: var(--text-primary);
    font-weight: 600;
}

.paper-content em {
    font-style: italic;
}

.paper-footer {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-default);
}

/* ── Contact ── */
.contact {
    text-align: center;
}

.contact-subheading {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 500px;
    margin: -1rem auto 2.5rem;
    line-height: 1.7;
}

.contact-grid {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.contact-card {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.5rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-default);
    border-radius: var(--border-radius);
    color: var(--text-primary);
    text-decoration: none;
    transition: all var(--transition);
    font-size: 0.95rem;
}

.contact-card i {
    font-size: 1.2rem;
    color: var(--accent-blue);
}

.contact-card-email:hover {
    border-color: var(--accent-blue);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(77, 148, 255, 0.15);
}

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

.contact-social-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    background: transparent;
    border: 1px solid var(--border-default);
    border-radius: 8px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-decoration: none;
    transition: all var(--transition);
}

.contact-social-link:hover {
    color: var(--text-primary);
    border-color: var(--text-secondary);
    transform: translateY(-2px);
}

.contact-social-link i {
    font-size: 1.1rem;
}


/* ── Footer ── */
.footer {
    padding: 2.5rem 0;
    text-align: center;
    border-top: 1px solid var(--border-default);
}

.footer p {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.footer a {
    color: var(--text-secondary);
}

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


/* ── Animations ── */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}


/* ── Responsive ── */
@media (max-width: 1024px) {
    .projects-grid {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 4rem 0;
    }

    .nav-toggle {
        display: block;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: rgba(13, 17, 23, 0.96);
        backdrop-filter: blur(12px);
        flex-direction: column;
        padding: 1rem 1.5rem 1.5rem;
        gap: 0;
        border-bottom: 1px solid var(--border-default);
    }

    .nav-links.open {
        display: flex;
    }

    .nav-link {
        padding: 0.75rem 0;
        display: block;
        border-bottom: 1px solid var(--border-muted);
    }

    .nav-link:last-child {
        border-bottom: none;
    }

    .nav-link::after {
        display: none;
    }

    .hero-name {
        font-size: 2.2rem;
    }

    .hero-title {
        font-size: 1rem;
    }

    .hero-avatar {
        width: 110px;
        height: 110px;
    }

    .hero-avatar-icon {
        font-size: 1.8rem;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }

    .stat-number {
        font-size: 2.2rem;
    }

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

    .section-heading {
        font-size: 1.5rem;
    }

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

    .paper-content h1 {
        font-size: 1.5rem;
    }

    .paper-content h2 {
        font-size: 1.15rem;
    }

    .contact-grid {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .hero-name {
        font-size: 1.8rem;
    }

    .stat-number {
        font-size: 1.8rem;
    }

    .stat-label {
        font-size: 0.75rem;
    }
}


/* ── Scrollbar ── */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-default);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}


/* ── Reduced motion ── */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    html {
        scroll-behavior: auto;
    }

    .fade-in {
        opacity: 1;
        transform: none;
    }
}