/* ============================================================
   ESTILOS DEL BLOG Y BIBLIOTECA ACADÉMICA - RESPONSIVO
   ============================================================ */

:root {
    --primary-color: #0284c7;
    --primary-dark: #0369a1;
    --primary-light: #e0f2fe;
    --text-dark: #0f172a;
    --text-muted: #64748b;
    --bg-light: #ffffff;
    --bg-alt: #f8fafc;
    --border-color: #e2e8f0;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 10px 25px rgba(0, 0, 0, 0.08);
    --radius-lg: 16px;
    --radius-md: 10px;
    --radius-sm: 6px;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', system-ui, -apple-system, Roboto, sans-serif;
}

body {
    background-color: var(--bg-alt);
    color: var(--text-dark);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-color);
    padding: 12px 0;
    position: sticky;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo img {
    height: 52px;
    border-radius: var(--radius-sm);
    object-fit: contain;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 30px;
}

.nav-list {
    list-style: none;
    display: flex;
    gap: 25px;
    margin: 0;
    padding: 0;
}

.nav-link {
    text-decoration: none;
    color: #334155;
    font-weight: 600;
    font-size: 0.98rem;
    position: relative;
    padding: 6px 2px;
    transition: color 0.25s ease;
}

.nav-link::after {
    content: "";
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 3px;
    background: var(--primary-color);
    border-radius: 2px;
    transition: width 0.25s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.header-user-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-greeting {
    display: flex;
    align-items: center;
    gap: 6px;
    color: #1e293b;
    font-weight: 600;
    font-size: 0.92rem;
}

.user-avatar {
    color: var(--primary-color);
    font-size: 1.25rem;
}

.btn-dashboard-nav {
    background: var(--primary-light);
    color: var(--primary-dark);
    padding: 8px 16px;
    border-radius: 20px;
    text-decoration: none;
    font-weight: 700;
    font-size: 0.88rem;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: all 0.2s ease;
}

.btn-dashboard-nav:hover {
    background: var(--primary-color);
    color: #ffffff;
}

.btn-logout {
    background: #fee2e2;
    color: #ef4444;
    padding: 7px 14px;
    border-radius: 20px;
    text-decoration: none;
    font-weight: 700;
    font-size: 0.88rem;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: all 0.2s ease;
}

.btn-logout:hover {
    background: #ef4444;
    color: #ffffff;
}

.btn-logout-nav {
    color: #ef4444;
    font-size: 1.1rem;
    padding: 6px 10px;
    border-radius: 8px;
    text-decoration: none;
    transition: background 0.2s ease;
}

.btn-logout-nav:hover {
    background: #fee2e2;
}

.btn-login {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: #ffffff;
    padding: 10px 22px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 700;
    font-size: 0.92rem;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 4px 12px rgba(2, 132, 199, 0.3);
    transition: all 0.25s ease;
}

.btn-login:hover {
    transform: translateY(-2px);
}

.hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
    padding: 6px;
}

.hamburger .bar {
    width: 26px;
    height: 3px;
    background-color: #1e293b;
    border-radius: 2px;
    transition: all 0.3s ease;
}

.hamburger.active .bar:nth-child(1) { transform: translateY(8px) rotate(45deg); }
.hamburger.active .bar:nth-child(2) { opacity: 0; }
.hamburger.active .bar:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }

/* Contenido Principal */
.blog-content {
    flex: 1;
    padding: 50px 0 80px 0;
}

.blog-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 50px auto;
}

.section-tag {
    color: var(--primary-color);
    font-weight: 800;
    text-transform: uppercase;
    font-size: 0.82rem;
    letter-spacing: 1px;
    display: block;
    margin-bottom: 8px;
}

.blog-header h1 {
    font-size: 2.2rem;
    font-weight: 800;
    color: #1e293b;
    margin-bottom: 12px;
}

.blog-header p {
    color: var(--text-muted);
    font-size: 1.05rem;
}

/* Grid de Artículos */
.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.blog-card {
    background: #ffffff;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    transition: all 0.3s ease;
}

.blog-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.blog-img-box {
    position: relative;
    height: 220px;
    overflow: hidden;
}

.blog-img-box img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.blog-card:hover .blog-img-box img {
    transform: scale(1.06);
}

.blog-category {
    position: absolute;
    top: 14px;
    left: 14px;
    background: rgba(2, 132, 199, 0.9);
    backdrop-filter: blur(4px);
    color: #ffffff;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.78rem;
    font-weight: 700;
}

.blog-card-body {
    padding: 24px;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.blog-meta {
    display: flex;
    gap: 15px;
    font-size: 0.82rem;
    color: #94a3b8;
    margin-bottom: 12px;
}

.blog-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.blog-card-body h3 {
    font-size: 1.25rem;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 10px;
    line-height: 1.35;
}

.blog-card-body p {
    font-size: 0.92rem;
    color: var(--text-muted);
    line-height: 1.55;
    margin-bottom: 22px;
    flex: 1;
}

.btn-download {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: #ffffff;
    padding: 11px 18px;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: 700;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: all 0.25s ease;
    box-shadow: 0 4px 10px rgba(2, 132, 199, 0.25);
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(2, 132, 199, 0.4);
    background: #0284c7;
}

/* Footer */
.footer {
    background: #0f172a;
    border-top: 1px solid #1e293b;
    margin-top: auto;
}

/* Responsividad */
@media (max-width: 992px) {
    .nav-menu {
        position: fixed;
        top: 75px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 75px);
        background: #ffffff;
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding: 35px 20px;
        gap: 25px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
        transition: left 0.35s ease;
        overflow-y: auto;
    }

    .nav-menu.active { left: 0; }
    .nav-list { flex-direction: column; align-items: center; gap: 20px; width: 100%; }
    .nav-link { font-size: 1.1rem; }
    .header-user-actions { flex-direction: column; width: 100%; gap: 15px; }
    .btn-login, .btn-dashboard-nav { width: 100%; max-width: 250px; justify-content: center; }
    .hamburger { display: flex; }
}

@media (max-width: 640px) {
    .blog-grid {
        grid-template-columns: 1fr;
    }
    .blog-header h1 {
        font-size: 1.75rem;
    }
}