/**
 * Abdur Rehman Portfolio - Layout Stylesheet
 * Handles structural frames: Header, Footer, Hero structure, flexible Grid systems, and page layouts.
 */

/* ==========================================================================
   1. Header / Navigation Layout
   ========================================================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background-color: transparent;
    border-bottom: 1px solid transparent;
    z-index: var(--z-header);
    transition: 
        height var(--transition-normal), 
        background-color var(--transition-normal), 
        border-color var(--transition-normal),
        box-shadow var(--transition-normal);
    display: flex;
    align-items: center;
}

/* Scrolled state applied via JS */
.header--scrolled {
    height: var(--header-height-scrolled);
    background-color: rgba(10, 15, 29, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
}

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

.nav__brand {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-family: var(--font-heading);
    font-size: var(--fs-md);
    font-weight: var(--fw-bold);
    color: var(--color-text-primary);
}

.nav__logo-mark {
    width: 32px;
    height: 32px;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--fs-sm);
    color: var(--color-bg);
    font-weight: var(--fw-bold);
    box-shadow: var(--glow-cyan);
}

.nav__list {
    display: none; /* Hidden on mobile */
}

@media (min-width: 768px) {
    .nav__list {
        display: flex;
        align-items: center;
        gap: var(--space-xl);
    }
}

.nav__item {
    position: relative;
}

.nav__link {
    font-family: var(--font-heading);
    font-size: var(--fs-sm);
    font-weight: var(--fw-medium);
    color: var(--color-text-secondary);
    padding: var(--space-xs) 0;
    transition: color var(--transition-fast);
}

.nav__link:hover,
.nav__link--active {
    color: var(--color-accent);
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: right;
    transition: transform var(--transition-normal);
}

.nav__link:hover::after,
.nav__link--active::after {
    transform: scaleX(1);
    transform-origin: left;
}

/* ==========================================================================
   2. Main Layout Sections
   ========================================================================== */
.main {
    padding-top: var(--header-height); /* Prevent content from slipping behind navigation bar */
    min-height: calc(100vh - var(--header-height));
    display: flex;
    flex-direction: column;
}

/* Hero Section Layout */
.hero-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
    align-items: center;
    min-height: calc(80vh - var(--header-height));
}

@media (min-width: 992px) {
    .hero-layout {
        grid-template-columns: 1.2fr 0.8fr;
        gap: var(--space-4xl);
    }
}

/* ==========================================================================
   3. Grid Architectures (Responsive)
   ========================================================================== */
.grid-2 {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-lg);
}

@media (min-width: 768px) {
    .grid-2 {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-xl);
    }
}

.grid-3 {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-lg);
}

@media (min-width: 768px) {
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 992px) {
    .grid-3 {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--space-xl);
    }
}

/* Responsive Grid for Filterable Portfolio Items */
.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-lg);
    margin-top: var(--space-2xl);
}

@media (min-width: 992px) {
    .portfolio-grid {
        grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
        gap: var(--space-xl);
    }
}

/* ==========================================================================
   4. Footer Layout
   ========================================================================== */
.footer {
    background-color: var(--color-bg-darker);
    border-top: 1px solid var(--border-color);
    padding-top: var(--space-2xl);
    padding-bottom: var(--space-xl);
    margin-top: auto; /* Push footer down if content is short */
}

.footer__layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
    margin-bottom: var(--space-2xl);
}

@media (min-width: 768px) {
    .footer__layout {
        grid-template-columns: 1.5fr 1fr 1fr;
        gap: var(--space-xl);
    }
}