:root {
    --bg-color: #111111;
    --surface-color: #1D1D1D;
    --accent-color: #3A7CFD;
    --text-primary: #F5F5F7;
    --text-secondary: #A0A0A0;
    --border-color: rgba(255, 255, 255, 0.1);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-secondary);
}

/* --- UTILITIES & BASE --- */
.section-padding { padding: 120px 0; }
.bg-surface { background-color: var(--surface-color); }
.section-title {
    font-size: clamp(2rem, 5vw, 2.5rem);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 3rem;
}

/* --- COMPONENTS --- */
.btn-primary {
    color: var(--text-primary);
    background-color: var(--accent-color);
    border: 1px solid var(--accent-color);
    padding: 0.8rem 2rem;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.25s ease;
}
.btn-primary:hover { background-color: #2c67d8; border-color: #2c67d8; }
.btn-outline-light {
    color: var(--text-primary);
    border-color: var(--border-color);
    padding: 0.8rem 2rem;
    border-radius: 8px;
    transition: all 0.25s ease;
}
.btn-outline-light:hover { background-color: var(--surface-color); border-color: var(--text-primary); }

/* --- SECTIONS --- */
.navbar {
    background: rgba(17, 17, 17, 0.7);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}
.navbar-brand { font-weight: 700; }
.nav-link { color: var(--text-secondary); transition: color 0.3s; }
.nav-link:hover, .nav-link.active { color: var(--text-primary); }

.hero {
    min-height: 100vh;
    display: flex; flex-direction: column; justify-content: center;
    text-align: left; max-width: 1000px; margin: auto; padding: 0 15px;
}
.hero-intro { color: var(--accent-color); font-size: 1.1rem; margin-bottom: 1rem; }
.hero-title { font-size: clamp(40px, 8vw, 72px); font-weight: 700; color: var(--text-primary); margin-bottom: 0.5rem; }
.hero-subtitle { font-size: clamp(40px, 8vw, 72px); font-weight: 700; color: var(--text-secondary); margin-bottom: 1.5rem; }
.hero-description { max-width: 540px; color: var(--text-secondary); }

#about .section-title { text-align: left; }
.about-text p { margin-bottom: 15px; font-size: 1.1rem; line-height: 1.7; }
.profile-pic-wrapper { max-width: 350px; margin: auto; position: relative; }
.profile-pic { width: 100%; border-radius: 12px; }

.project-card {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 30px;
    height: 100%;
    transition: background-color 0.25s ease-in-out, transform 0.25s ease;
}
.project-card:hover { transform: translateY(-5px); background-color: #2a2a2a; }
.project-card h5 { color: var(--text-primary); font-weight: 700; }
.project-card p { color: var(--text-secondary); }
.project-card { display: flex; flex-direction: column; }
.project-card p { flex-grow: 1; margin-top: 10px; }
.project-card .links { text-align: right; margin-top: 1rem; }
.project-card .links a { color: var(--text-secondary); font-size: 1.5rem; margin-left: 20px; transition: color 0.25s ease; }
.project-card .links a:hover { color: var(--accent-color); }
.project-card .links .in-progress { color: #888; }


/* --- NEW Experience Tabs --- */
.experience-tabs {
    display: flex;
    min-height: 340px;
    max-width: 800px;
    margin: 0 auto;
}
/* Tab buttons on the left */
.experience-tabs .nav-pills .nav-link {
    padding: 10px 20px;
    height: auto;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    text-align: left;
    border-radius: 4px;
    font-weight: 500;
    color: var(--text-secondary);
    border-left: 2px solid var(--border-color);
    margin-bottom: 2px;
}
.experience-tabs .nav-pills .nav-link.active,
.experience-tabs .nav-pills .show > .nav-link {
    color: var(--accent-color);
    background-color: rgba(58, 124, 253, 0.1);
    border-left-color: var(--accent-color);
}
/* Content panels on the right */
.experience-tabs .tab-content {
    width: 100%;
    padding-left: 25px;
}
.experience-tabs .tab-pane h5 {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text-primary);
}
.experience-tabs .tab-pane .date {
    color: #888;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}
.experience-tabs .tab-pane .exp-details {
    padding-left: 20px;
    list-style: none;
}
.experience-tabs .tab-pane .exp-details li {
    position: relative;
    margin-bottom: 10px;
    padding-left: 15px;
}
.experience-tabs .tab-pane .exp-details li::before {
    content: "▹";
    position: absolute;
    left: -10px;
    top: 0px;
    color: var(--accent-color);
    line-height: inherit;
}


/* --- NEW Certifications Grid --- */
.cert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1.5rem;
}
.cert-card {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 25px 20px;
    text-align: center;
    transition: transform 0.25s ease, background-color 0.25s ease;
}
.cert-card:hover {
    transform: translateY(-5px);
    background-color: var(--surface-color);
}
.cert-card img {
    height: 45px;
    max-width: 100%;
    object-fit: contain;
    margin-bottom: 15px;
}
.cert-card p {
    color: var(--text-secondary);
    font-weight: 500;
    margin: 0;
}


#contact { padding-bottom: 80px; }
.footer { padding: 30px 0; border-top: 1px solid var(--border-color); }
.footer .social-links a { font-size: 1.5rem; color: var(--text-secondary); margin: 0 10px; transition: color 0.25s ease; }
.footer .social-links a:hover { color: var(--text-primary); }
.footer p { color: #888; font-size: 0.9rem; margin-top: 15px; }


/* --- ANIMATION --- */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}
.reveal.is-visible {
    opacity: 1;
    transform: translateY(0);
}
.hero .reveal:nth-child(1) { transition-delay: 100ms; }
.hero .reveal:nth-child(2) { transition-delay: 200ms; }
.hero .reveal:nth-child(3) { transition-delay: 300ms; }
.hero .reveal:nth-child(4) { transition-delay: 400ms; }
.hero .reveal:nth-child(5) { transition-delay: 500ms; }


/* --- RESPONSIVE --- */
@media (max-width: 768px) {
    .experience-tabs {
        flex-direction: column;
    }
    .experience-tabs .nav-pills {
        flex-direction: row !important;
        overflow-x: auto;
        white-space: nowrap;
        margin-bottom: 20px;
        border-bottom: 1px solid var(--border-color);
    }
    .experience-tabs .nav-pills .nav-link {
        border-bottom: 2px solid transparent;
        border-left: none;
        text-align: center;
    }
    .experience-tabs .nav-pills .nav-link.active {
        border-bottom-color: var(--accent-color);
    }
    .experience-tabs .tab-content {
        padding-left: 0;
    }
}