/* ==========================================================================
   1. VARIABLES & RESET
   ========================================================================== */
:root {
    --bg-dark: #0a0a0a;
    --accent-blue: #6A97AC;
    --text-gray: #a0a0a0;
    --glass: rgba(255, 255, 255, 0.05);
    --border: rgba(255, 255, 255, 0.08);
    --transition-smooth: 0.5s cubic-bezier(0.2, 1, 0.3, 1);
}

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

body {
    background-color: var(--bg-dark);
    color: #ffffff;
    font-family: 'Plus Jakarta Sans', sans-serif;
    overflow-x: hidden;
    line-height: 1.6;
}

.grid-bg {
    position: fixed;
    inset: 0;
    z-index: -2;
    background-image: 
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 50px 50px;
    opacity: 0.8;
}

/* ==========================================================================
   2. NAVIGATION
   ========================================================================== */
.back-navigation {
    position: fixed;
    top: 40px;
    left: 5%;
    z-index: 1000;
}

.back-btn {
    text-decoration: none;
    color: white;
    background: var(--glass);
    border: 1px solid var(--border);
    padding: 12px 24px;
    border-radius: 100px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: var(--transition-smooth);
    backdrop-filter: blur(10px);
}

.back-btn:hover {
    background: var(--accent-blue);
    color: #000;
    border-color: var(--accent-blue);
    transform: translateX(-5px);
}

/* ==========================================================================
   3. CERTIFICATE GRID & CARDS
   ========================================================================== */
.portfolio-container {
    padding-top: 150px; 
    max-width: 1250px;
    margin: 0 auto;
    padding-inline: 5%;
    min-height: 100vh;
}

.portfolio-header { text-align: center; margin-bottom: 60px; }
.portfolio-header h1 { font-size: clamp(30px, 5vw, 55px); font-weight: 800; margin-top: 15px; }
.tag { color: var(--accent-blue); font-weight: 800; letter-spacing: 3px; font-size: 12px; text-transform: uppercase; }
.text-blue { color: var(--accent-blue); }

.cert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 30px;
    margin-bottom: 80px;
}

.cert-card {
    background: var(--glass);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-radius: 30px;
    overflow: hidden;
    transition: var(--transition-smooth);
    display: flex;
    flex-direction: column;
}

.cert-card:hover {
    transform: translateY(-10px);
    border-color: var(--accent-blue);
    box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}

.cert-img-wrapper {
    width: 100%;
    aspect-ratio: 4 / 3;
    overflow: hidden;
    background: #1a1a1a;
    border-bottom: 1px solid var(--border);
}

.cert-img-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.6s ease;
}

.cert-card:hover .cert-img-wrapper img {
    transform: scale(1.05);
}

.cert-details { padding: 30px; }

.cert-issuer {
    display: block;
    color: var(--accent-blue);
    font-size: 11px;
    font-weight: 800;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 10px;
}

.cert-details h3 { font-size: 22px; color: white; margin-bottom: 12px; line-height: 1.3; }

.cert-details p {
    color: var(--text-gray);
    font-size: 14px;
    line-height: 1.6;
    margin-bottom: 25px;
}

.cert-date {
    display: block;
    font-size: 12px;
    font-style: italic;
    color: var(--text-gray);
    opacity: 0.6;
}

/* ==========================================================================
   4. FOOTER
   ========================================================================== */
footer {
    padding: 60px 5% 40px;
    border-top: 1px solid var(--border);
    background-color: var(--bg-dark); 
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-gray);
    font-size: 13px;
}

@media (max-width: 768px) {
    .cert-grid { grid-template-columns: 1fr; }
    .footer-bottom { flex-direction: column; gap: 15px; text-align: center; }
}