/* ============================================================
   CSS Custom Properties
   ============================================================ */
:root {
    --color-bg:         #0f172a;
    --color-surface:    #1e293b;
    --color-primary:    #6366f1;
    --color-primary-h:  #4f46e5;
    --color-text:       #e2e8f0;
    --color-text-muted: #94a3b8;
    --color-border:     #334155;
    --font-sans:        'Segoe UI', system-ui, -apple-system, sans-serif;
    --font-mono:        'Cascadia Code', 'Fira Code', monospace;
    --radius:           0.5rem;
    --transition:       0.25s ease;
    --shadow:           0 4px 24px rgba(0,0,0,0.4);
    --container-width:  1100px;
}

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

html { scroll-behavior: smooth; }

body {
    background-color: var(--color-bg);
    color: var(--color-text);
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.7;
}

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

a { color: var(--color-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-primary-h); }

ul { list-style: none; }

/* ============================================================
   Utility
   ============================================================ */
.container {
    max-width: var(--container-width);
    margin-inline: auto;
    padding-inline: 1.5rem;
}

.section {
    padding-block: 6rem;
}

.section__title {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
}

.section__title::after {
    content: '';
    display: block;
    width: 3rem;
    height: 4px;
    background: var(--color-primary);
    border-radius: 2px;
    margin: 0.75rem auto 0;
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.75rem;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    border: 2px solid transparent;
    transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.btn--primary {
    background: var(--color-primary);
    color: #fff;
}
.btn--primary:hover { background: var(--color-primary-h); color: #fff; }

.btn--outline {
    background: transparent;
    border-color: var(--color-primary);
    color: var(--color-primary);
}
.btn--outline:hover { background: var(--color-primary); color: #fff; }

.btn--sm { padding: 0.5rem 1.1rem; font-size: 0.85rem; }
.btn--full { width: 100%; justify-content: center; }

/* ============================================================
   Navbar
   ============================================================ */
.navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    transition: box-shadow var(--transition);
}

.navbar--scrolled { box-shadow: var(--shadow); }

.navbar__container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 4rem;
}

.navbar__logo {
    font-size: 1.25rem;
    font-weight: 700;
    font-family: var(--font-mono);
    color: var(--color-primary);
}

.navbar__menu {
    display: flex;
    gap: 2rem;
}

.navbar__link {
    color: var(--color-text-muted);
    font-size: 0.95rem;
    font-weight: 500;
    transition: color var(--transition);
}
.navbar__link:hover { color: var(--color-text); }

.navbar__toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 4px; }
.navbar__toggle span { display: block; width: 22px; height: 2px; background: var(--color-text); border-radius: 2px; transition: var(--transition); }

/* ============================================================
   Hero
   ============================================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 4rem;
    background: radial-gradient(ellipse at 60% 40%, rgba(99,102,241,0.15) 0%, transparent 60%);
}

.hero__container {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.hero__greeting { color: var(--color-primary); font-family: var(--font-mono); font-size: 1rem; }

.hero__name {
    font-size: clamp(2.5rem, 7vw, 5rem);
    font-weight: 800;
    line-height: 1.1;
}

.hero__title {
    font-size: clamp(1.25rem, 3vw, 2rem);
    color: var(--color-text-muted);
    font-weight: 400;
}

.hero__description { max-width: 540px; color: var(--color-text-muted); font-size: 1.05rem; }

.hero__actions { display: flex; gap: 1rem; flex-wrap: wrap; }

.hero__social {
    display: flex;
    gap: 1.25rem;
    margin-top: 0.5rem;
}

.hero__social a {
    color: var(--color-text-muted);
    transition: color var(--transition);
}
.hero__social a:hover { color: var(--color-primary); }

/* ============================================================
   About
   ============================================================ */
.about { background: var(--color-surface); }

.about__grid {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 4rem;
    align-items: center;
}

.about__image img {
    border-radius: 50%;
    width: 220px;
    height: 220px;
    object-fit: cover;
    border: 4px solid var(--color-primary);
    margin-inline: auto;
}

.about__content p { color: var(--color-text-muted); margin-bottom: 1rem; }
.about__content .btn { margin-top: 1rem; }

/* ============================================================
   Skills
   ============================================================ */
.skills__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
}

.skills__card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.75rem;
    transition: border-color var(--transition), transform var(--transition);
}
.skills__card:hover { border-color: var(--color-primary); transform: translateY(-4px); }

.skills__category {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 1rem;
}

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

.skills__item {
    background: rgba(99,102,241,0.12);
    color: var(--color-text);
    padding: 0.3rem 0.8rem;
    border-radius: 999px;
    font-size: 0.875rem;
    font-family: var(--font-mono);
}

/* ============================================================
   Projects
   ============================================================ */
.projects { background: var(--color-surface); }

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

.project-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 1.75rem;
    transition: border-color var(--transition), transform var(--transition);
}
.project-card:hover { border-color: var(--color-primary); transform: translateY(-4px); }

.project-card__title { font-size: 1.15rem; font-weight: 700; margin-bottom: 0.75rem; }
.project-card__description { color: var(--color-text-muted); font-size: 0.95rem; margin-bottom: 1rem; }

.project-card__tags { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1.25rem; }

.tag {
    background: rgba(99,102,241,0.12);
    color: var(--color-primary);
    padding: 0.2rem 0.7rem;
    border-radius: 999px;
    font-size: 0.8rem;
    font-family: var(--font-mono);
}

.project-card__links { display: flex; gap: 0.75rem; }

/* ============================================================
   Experience
   ============================================================ */
.experience {
    position: relative;
}

.experience::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 18% 10%, rgba(99, 102, 241, 0.12), transparent 45%);
    pointer-events: none;
}

.experience .container {
    position: relative;
    z-index: 1;
}

.experience__lead {
    max-width: 720px;
    margin: -1.25rem auto 2.25rem;
    text-align: center;
    color: var(--color-text-muted);
}

.experience__grid {
    display: grid;
    gap: 1rem;
}

.experience-card {
    display: grid;
    grid-template-columns: 30px 1fr;
    gap: 1rem;
    padding: 1.35rem;
    border-radius: var(--radius);
    border: 1px solid var(--color-border);
    background: linear-gradient(180deg, rgba(30, 41, 59, 0.95), rgba(15, 23, 42, 0.95));
    transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.experience-card:hover {
    border-color: rgba(99, 102, 241, 0.8);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.experience-card__rail {
    position: relative;
    display: flex;
    justify-content: center;
}

.experience-card__rail::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, rgba(99, 102, 241, 0.75), rgba(99, 102, 241, 0.12));
}

.experience-card:last-child .experience-card__rail::before {
    bottom: 40%;
}

.experience-card__dot {
    width: 12px;
    height: 12px;
    margin-top: 0.4rem;
    border-radius: 50%;
    background: var(--color-primary);
    box-shadow: 0 0 0 5px rgba(99, 102, 241, 0.2);
    position: relative;
    z-index: 1;
}

.experience-card__header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 0.75rem;
}

.experience-card__title {
    font-size: 1.1rem;
    line-height: 1.3;
}

.experience-card__period {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--color-primary);
    border: 1px solid rgba(99, 102, 241, 0.45);
    padding: 0.2rem 0.55rem;
    border-radius: 999px;
    white-space: nowrap;
}

.experience-card__company {
    color: var(--color-text-muted);
    margin-top: 0.3rem;
    font-weight: 600;
}

.experience-card__description {
    margin-top: 0.75rem;
    color: var(--color-text-muted);
}

.experience-card__tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    margin-top: 0.95rem;
}

.experience-card__links {
    grid-column: 2 / -1;
    display: flex;
    gap: 0.65rem;
    margin-top: 0.55rem;
}

/* ============================================================
   Education
   ============================================================ */
.education {
    background: var(--color-surface);
}

.education__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
}

.education-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.15rem;
    transition: border-color var(--transition), transform var(--transition);
}

.education-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-3px);
}

.education-card__header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 0.75rem;
}

.education-card__title {
    font-size: 1rem;
    line-height: 1.35;
}

.education-card__year {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--color-primary);
    border: 1px solid rgba(99, 102, 241, 0.45);
    padding: 0.2rem 0.55rem;
    border-radius: 999px;
    white-space: nowrap;
}

.education-card__institution {
    margin-top: 0.55rem;
    color: var(--color-text);
    font-weight: 600;
}

.education-card__location {
    color: var(--color-text-muted);
    font-size: 0.93rem;
}

/* ============================================================
   Contact
   ============================================================ */
.contact__grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 4rem;
    align-items: start;
}

.contact__info p { color: var(--color-text-muted); margin-bottom: 1.25rem; }
.contact__email { font-size: 1.05rem; font-weight: 600; }

.contact__form { display: flex; flex-direction: column; gap: 1.25rem; }

.form-group { display: flex; flex-direction: column; gap: 0.4rem; }

.form-group label { font-size: 0.9rem; font-weight: 600; color: var(--color-text-muted); }

.form-group input,
.form-group textarea {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    color: var(--color-text);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    padding: 0.75rem 1rem;
    transition: border-color var(--transition);
    resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

/* ============================================================
   Footer
   ============================================================ */
.footer {
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding-block: 2rem;
}

.footer__container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer p { color: var(--color-text-muted); font-size: 0.9rem; }
.footer__links { display: flex; gap: 1.5rem; }
.footer__links a { color: var(--color-text-muted); font-size: 0.9rem; }
.footer__links a:hover { color: var(--color-primary); }

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 768px) {
    .navbar__menu {
        display: none;
        position: absolute;
        top: 4rem; left: 0; right: 0;
        flex-direction: column;
        background: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        padding: 1.5rem;
        gap: 1.25rem;
    }
    .navbar__menu.open { display: flex; }
    .navbar__toggle { display: flex; }

    .about__grid,
    .contact__grid { grid-template-columns: 1fr; gap: 2rem; }

    .experience-card {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .experience-card__rail {
        display: none;
    }

    .experience-card__links {
        grid-column: 1;
        flex-wrap: wrap;
    }

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

    .education-card__header {
        flex-direction: column;
    }

    .about__image img { width: 160px; height: 160px; }
}