/* ============================================
   INDEX.CSS - Estilos exclusivos de index.html
   Proyecto: Cálculo Integral
   ============================================ */

/* ============================================
   HERO SECTION
   ============================================ */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--bg-dark-light) 100%);
    overflow: hidden;
}

#heroCanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: white;
    padding: 2rem;
    max-width: 800px;
}

.hero-content h1 {
    font-size: clamp(2rem, 6vw, 3.5rem);
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.text-gradient {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: rgba(255,255,255,0.8);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.hero-text {
    font-size: 1.1rem;
    color: rgba(255,255,255,0.9);
    margin-bottom: 2rem;
}

.btn-hero {
    display: inline-block;
    padding: 1rem 2.5rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    text-decoration: none;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 1.1rem;
    transition: var(--transition-normal);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-hero:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.5);
    color: white;
}

/* ============================================
   SECCIÓN INTRODUCCIÓN
   ============================================ */
.section-intro {
    padding: 5rem 0;
    background: var(--bg-light);
}

.section-title {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.section-subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
}

/* Tarjetas de introducción */
.intro-card {
    background: white;
    border-radius: var(--radius-lg);
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    height: 100%;
}

.intro-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.intro-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2rem;
}

.intro-icon-orange {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    color: #d97706;
}

.intro-icon-blue {
    background: linear-gradient(135deg, #dbeafe 0%, #bfdbfe 100%);
    color: #2563eb;
}

.intro-icon-green {
    background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
    color: #059669;
}

.intro-card h5 {
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--text-dark);
}

.intro-card p {
    color: var(--text-muted);
    margin-bottom: 0;
    font-size: 0.95rem;
}

/* Big idea box */
.big-idea {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 1.25rem 2rem;
    border-radius: var(--radius-full);
    font-size: 1.1rem;
    box-shadow: var(--shadow-lg);
}

.big-idea i {
    font-size: 1.5rem;
    color: #fbbf24;
}

/* ============================================
   SELECTOR DE UNIDADES
   ============================================ */
.section-unidades {
    padding: 5rem 0;
    background: var(--bg-white);
}

.unidad-card-link {
    text-decoration: none;
    display: block;
}

.unidad-card {
    background: white;
    border-radius: var(--radius-lg);
    padding: 2rem;
    height: 100%;
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
    border: 2px solid transparent;
}

.unidad-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
}

.unidad-card-1 { border-color: #667eea; }
.unidad-card-2 { border-color: #f59e0b; }
.unidad-card-3 { border-color: #10b981; }

.unidad-card-1:hover { background: linear-gradient(135deg, #eef2ff 0%, #e0e7ff 100%); }
.unidad-card-2:hover { background: linear-gradient(135deg, #fffbeb 0%, #fef3c7 100%); }
.unidad-card-3:hover { background: linear-gradient(135deg, #ecfdf5 0%, #d1fae5 100%); }

.unidad-numero {
    position: absolute;
    top: -20px;
    right: -20px;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    font-weight: 700;
    opacity: 0.15;
}

.unidad-card-1 .unidad-numero { background: #667eea; color: #667eea; }
.unidad-card-2 .unidad-numero { background: #f59e0b; color: #f59e0b; }
.unidad-card-3 .unidad-numero { background: #10b981; color: #10b981; }

.unidad-contenido {
    position: relative;
    z-index: 1;
}

.unidad-contenido h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--text-dark);
}

.unidad-contenido > p {
    color: var(--text-muted);
    margin-bottom: 1.25rem;
    font-size: 0.95rem;
}

.unidad-temas {
    list-style: none;
    padding: 0;
    margin: 0 0 1.5rem 0;
}

.unidad-temas li {
    padding: 0.35rem 0;
    padding-left: 1.25rem;
    position: relative;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.unidad-temas li::before {
    content: "✓";
    position: absolute;
    left: 0;
    font-weight: bold;
}

.unidad-card-1 .unidad-temas li::before { color: #667eea; }
.unidad-card-2 .unidad-temas li::before { color: #f59e0b; }
.unidad-card-3 .unidad-temas li::before { color: #10b981; }

.unidad-cta {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    transition: var(--transition-fast);
}

.unidad-card-1 .unidad-cta { color: #667eea; }
.unidad-card-2 .unidad-cta { color: #f59e0b; }
.unidad-card-3 .unidad-cta { color: #10b981; }

.unidad-card:hover .unidad-cta {
    gap: 1rem;
}

/* ============================================
   RESPONSIVE INDEX
   ============================================ */
@media (max-width: 767.98px) {
    .hero-content h1 {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .big-idea {
        flex-direction: column;
        text-align: center;
        padding: 1.5rem;
        border-radius: var(--radius-lg);
    }
    
    .section-intro {
        padding: 3rem 0;
    }
    
    .section-unidades {
        padding: 3rem 0;
    }
    
    .unidad-card {
        padding: 1.5rem;
    }
    
    .unidad-contenido h3 {
        font-size: 1.25rem;
    }
}