:root {
    --bg: #050816;
    --bg-alt: #0b1020;
    --bg-card: #111827;
    --border-subtle: rgba(255, 255, 255, 0.06);
    --text: #f9fafb;
    --muted: #9ca3af;
    --accent: #6366f1;
    --accent-soft: rgba(99, 102, 241, 0.16);
    --accent-strong: #4f46e5;
    --nav-height: 70px;
    --shadow-soft: 0 18px 45px rgba(15, 23, 42, 0.75);
    --radius-lg: 24px;
}

body.light-theme {
    --bg: #f9fafb;
    --bg-alt: #ffffff;
    --bg-card: #ffffff;
    --border-subtle: rgba(15, 23, 42, 0.08);
    --text: #020617;
    --muted: #6b7280;
    --accent: #4f46e5;
    --accent-soft: rgba(79, 70, 229, 0.12);
    --accent-strong: #4338ca;
    --shadow-soft: 0 14px 35px rgba(15, 23, 42, 0.18);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Poppins", sans-serif;
    background: radial-gradient(circle at top left, #111827 0, var(--bg) 40%, #020617 100%);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

a {
    color: inherit;
    text-decoration: none;
}

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

/* Layout */
.container {
    width: min(1120px, 100% - 2.5rem);
    margin: 0 auto;
}

section {
    padding: 100px 0;
}

.section-title {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    text-align: center;
}

.section-subtitle {
    color: var(--muted);
    margin-bottom: 2.5rem;
    text-align: center;
}

/* Navbar */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    z-index: 50;
    backdrop-filter: blur(14px);
    background: linear-gradient(to bottom,
    rgba(15, 23, 42, 0.92),
    rgba(15, 23, 42, 0.72),
    transparent);
    border-bottom: 1px solid rgba(148, 163, 184, 0.15);
}

.nav-inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.65rem;
    font-weight: 600;
    letter-spacing: 0.06em;
}

.brand-logo {
    width: 38px;
    height: 38px;
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.35);
    background: radial-gradient(circle at 30% 0, #a5b4fc 0, #6366f1 40%, #111827 100%);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.95rem;
    box-shadow: 0 10px 25px rgba(79, 70, 229, 0.55);
    color: #e5e7eb;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 1.75rem;
    font-size: 0.95rem;
}

nav a {
    color: var(--muted);
    transition: color 0.2s linear;
    position: relative;
}

nav a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -4px;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #a855f7, #6366f1, #22d3ee);
    border-radius: 999px;
    transition: width 0.22s ease-out;
}

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

nav a:hover::after {
    width: 100%;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.btn-small-outline {
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.4);
    padding: 0.45rem 0.85rem;
    font-size: 0.8rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
    cursor: pointer;
    background: radial-gradient(circle at top left,
    rgba(148, 163, 184, 0.3),
    rgba(15, 23, 42, 0.8));
    color: var(--text);
}

.btn-small-outline i {
    font-size: 0.85rem;
}

.btn-theme-toggle {
    width: 34px;
    height: 34px;
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.45);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    background: radial-gradient(circle at 0% 0%, #1e293b 0%, #020617 55%, #020617 100%);
    color: #e5e7eb;
}

.btn-theme-toggle i {
    font-size: 0.95rem;
}

/* Hero */
#home {
    padding-top: calc(80px + var(--nav-height));
    padding-bottom: 90px;
}

.hero {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 3.5rem;
    align-items: center;
}

.hero-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    background: linear-gradient(90deg, rgba(79,70,229,0.16), rgba(14,165,233,0.08));
    border-radius: 9999px;
    padding: 0.25rem 0.85rem;
    border: 1px solid rgba(129, 140, 248, 0.55);
    font-size: 0.8rem;
    color: #c7d2fe;
    margin-bottom: 0.75rem;
}

.hero-title {
    font-size: clamp(2.3rem, 3.1vw, 3rem);
    font-weight: 700;
    margin-bottom: 0.4rem;
}

.hero-title span {
    background: linear-gradient(90deg, #a855f7, #6366f1, #06b6d4);
    -webkit-background-clip: text;
    color: transparent;
}

.hero-role {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 0.75rem;
    color: #c4c9ff;
    min-height: 1.4em;
}

.hero-text {
    color: var(--muted);
    max-width: 32rem;
    margin-bottom: 1.3rem;
    font-size: 0.98rem;
}

.hero-meta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 1.25rem;
    margin-bottom: 1.75rem;
}

.hero-meta-item {
    display: flex;
    align-items: center;
    gap: 0.45rem;
    font-size: 0.85rem;
    color: var(--muted);
}

.hero-meta-item i {
    color: #a5b4fc;
    font-size: 0.9rem;
}

.hero-cta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.9rem;
}

.btn-primary,
.btn-ghost {
    padding: 0.7rem 1.25rem;
    border-radius: 999px;
    border: 1px solid transparent;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    transition: transform 0.12s ease-out, box-shadow 0.12s ease-out, background 0.12s ease-out, border 0.12s ease-out;
}

.btn-primary {
    background: linear-gradient(135deg, #4f46e5, #8b5cf6);
    color: #f9fafb;
    box-shadow: 0 18px 40px rgba(37, 99, 235, 0.55);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 20px 50px rgba(59, 130, 246, 0.7);
}

.btn-ghost {
    background: transparent;
    color: var(--text);
    border-color: rgba(148, 163, 184, 0.6);
}

.btn-ghost:hover {
    background: rgba(15, 23, 42, 0.7);
    transform: translateY(-1px);
}

.hero-socials {
    display: flex;
    gap: 0.8rem;
    margin-top: 1.25rem;
}

.social-icon {
    width: 34px;
    height: 34px;
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.45);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: #e5e7eb;
    background: radial-gradient(circle at 0% 0%, #1e293b 0%, #020617 55%, #020617 100%);
    font-size: 0.9rem;
    transition: transform 0.12s ease-out, box-shadow 0.12s ease-out, border 0.12s ease-out;
}

.social-icon:hover {
    transform: translateY(-1px);
    box-shadow: 0 10px 24px rgba(15, 23, 42, 0.65);
    border-color: #6366f1;
}
.hero-photo-wrap {
    justify-self: center;
}

.hero-photo-box {
    position: relative;
    width: min(320px, 75vw);
    aspect-ratio: 1/1;
    border-radius: 999px;
    background: none; /* removed gradient background */
    padding: 0;        /* removed padding ring */
    box-shadow: none;  /* removed shadow */
    overflow: hidden;
}

.hero-photo-inner {
    position: relative;
    width: 100%;
    height: 100%;
    border-radius: 999px;
    overflow: hidden;
    border: none; /* removed border outline */
}

.hero-photo-inner img {
    object-fit: cover;
    width: 100%;
    height: 100%;
    transform: none;  /* no unwanted zooming */
}

.hero-photo-glow {
    display: none; /* remove glow */
}


/* About */
.about-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 2.5rem;
    align-items: start;
}

.about-text {
    color: var(--muted);
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

.about-highlight {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 1rem;
}

.pill {
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.5);
    padding: 0.35rem 0.85rem;
    font-size: 0.8rem;
    color: var(--muted);
    background: rgba(15, 23, 42, 0.6);
}

.about-card {
    padding: 1.25rem 1.4rem;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(148, 163, 184, 0.25);
    background: radial-gradient(circle at 0% 0%, rgba(148,163,184,0.16), rgba(15,23,42,0.95));
    box-shadow: var(--shadow-soft);
    font-size: 0.86rem;
    color: var(--muted);
}

.about-card h3 {
    font-size: 0.95rem;
    margin-bottom: 0.4rem;
    color: var(--text);
}

/* Experience */
.timeline {
    display: flex;
    flex-direction: column;
    gap: 1.75rem;
}

.timeline-item {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    gap: 1rem;
}

.timeline-marker {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.timeline-dot {
    width: 12px;
    height: 12px;
    border-radius: 999px;
    background: #6366f1;
    box-shadow: 0 0 15px rgba(129, 140, 248, 0.9);
}

.timeline-line {
    flex: 1;
    width: 1.5px;
    background: linear-gradient(to bottom, rgba(148, 163, 184, 0.65), transparent);
}

.timeline-card {
    padding: 1.25rem 1.4rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    background: var(--bg-card);
    box-shadow: var(--shadow-soft);
}

.timeline-card-header {
    display: flex;
    justify-content: space-between;
    gap: 0.75rem;
    margin-bottom: 0.4rem;
}

.timeline-role {
    font-weight: 600;
    font-size: 1rem;
}

.timeline-company {
    color: var(--muted);
    font-size: 0.87rem;
}

.timeline-date {
    font-size: 0.8rem;
    color: var(--muted);
}

.timeline-card ul {
    margin-left: 1.1rem;
    margin-top: 0.35rem;
    color: var(--muted);
    font-size: 0.9rem;
}

.timeline-card li + li {
    margin-top: 0.25rem;
}

/* Skills */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1rem;
}

.skill-card {
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    background: radial-gradient(circle at top left,
    rgba(79, 70, 229, 0.18),
    rgba(15, 23, 42, 0.98));
    padding: 1.1rem 1.2rem;
    box-shadow: var(--shadow-soft);
}

.skill-card h3 {
    font-size: 0.98rem;
    margin-bottom: 0.35rem;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-top: 0.6rem;
}

.skill-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    border-radius: 999px;
    padding: 0.25rem 0.6rem;
    background: rgba(15, 23, 42, 0.9);
    border: 1px solid rgba(148, 163, 184, 0.55);
    font-size: 0.78rem;
    color: #e5e7eb;
}

.skill-tag i {
    font-size: 0.9rem;
}

/* Projects */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.2rem;
}

.project-card {
    position: relative;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    background: radial-gradient(circle at top left,
    rgba(129, 140, 248, 0.16),
    rgba(15, 23, 42, 0.98));
    padding: 1.1rem 1.2rem 1.25rem;
    box-shadow: var(--shadow-soft);
    overflow: hidden;
    transition: transform 0.16s ease-out, box-shadow 0.18s ease-out, border 0.16s ease-out;
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 22px 50px rgba(15, 23, 42, 0.95);
    border-color: rgba(129, 140, 248, 0.8);
}

.project-title-row {
    display: flex;
    justify-content: space-between;
    gap: 0.75rem;
    align-items: center;
    margin-bottom: 0.3rem;
}

.project-title {
    font-size: 1rem;
    font-weight: 600;
}

.project-badge {
    font-size: 0.7rem;
    padding: 0.18rem 0.55rem;
    border-radius: 999px;
    background: rgba(34, 197, 94, 0.18);
    border: 1px solid rgba(34, 197, 94, 0.55);
    color: #bbf7d0;
    white-space: nowrap;
}

.project-desc {
    font-size: 0.86rem;
    color: var(--muted);
    margin-bottom: 0.6rem;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.35rem;
    margin-bottom: 0.6rem;
}

.project-tech span {
    font-size: 0.72rem;
    border-radius: 999px;
    padding: 0.18rem 0.55rem;
    background: rgba(15, 23, 42, 0.9);
    border: 1px solid rgba(148, 163, 184, 0.55);
    color: #e5e7eb;
}

.project-links {
    display: flex;
    justify-content: flex-start;
    gap: 0.6rem;
    font-size: 0.8rem;
}

.project-link {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    color: #c7d2fe;
}

.project-link i {
    font-size: 0.8rem;
}

.projects-footer {
    margin-top: 1.8rem;
    display: flex;
    justify-content: center;
}

/* Certifications & Publications */
.simple-card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1rem;
}

.simple-card {
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    background: var(--bg-card);
    padding: 1.1rem 1.2rem;
    box-shadow: var(--shadow-soft);
    font-size: 0.88rem;
    color: var(--muted);
}

.simple-card h3 {
    font-size: 0.95rem;
    margin-bottom: 0.35rem;
    color: var(--text);
}

.simple-card span {
    font-size: 0.78rem;
    color: var(--muted);
}

/* Resume section */
.resume-wrapper {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
}

.resume-text {
    max-width: 520px;
    color: var(--muted);
    font-size: 0.92rem;
}

/* Contact */
.contact-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    gap: 2.5rem;
    align-items: start;
}

.contact-text {
    color: var(--muted);
    font-size: 0.93rem;
    margin-bottom: 1rem;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    font-size: 0.88rem;
    color: var(--muted);
}

.contact-details span i {
    margin-right: 0.45rem;
    color: #a5b4fc;
}

form {
    display: grid;
    gap: 0.8rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    font-size: 0.82rem;
}

.form-group label {
    color: var(--muted);
}

.form-group input,
.form-group textarea {
    border-radius: 0.9rem;
    border: 1px solid rgba(148, 163, 184, 0.45);
    background: rgba(15, 23, 42, 0.85);
    padding: 0.6rem 0.8rem;
    color: var(--text);
    font-family: inherit;
    font-size: 0.86rem;
}

body.light-theme .form-group input,
body.light-theme .form-group textarea {
    background: rgba(248, 250, 252, 0.9);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.btn-submit {
    width: fit-content;
}

/* Footer */
footer {
    border-top: 1px solid rgba(148, 163, 184, 0.25);
    padding: 1.1rem 0 1.3rem;
    font-size: 0.8rem;
    color: var(--muted);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

/* Responsive */
@media (max-width: 900px) {
    .hero,
    .about-grid,
    .contact-grid {
    grid-template-columns: 1fr;
    }

    .hero {
    text-align: left;
    }

    .hero-photo-wrap {
    order: -1;
    }

    header {
    background: rgba(15, 23, 42, 0.96);
    }

    nav ul {
    display: none; /* keep nav simple on mobile; could be upgraded to hamburger */
    }
}

@media (max-width: 640px) {
    #home {
    padding-top: calc(90px + var(--nav-height));
    }
    section {
    padding: 80px 0;
    }
}