/* ==========================================================================
   DISEÑO OPTIMIZADO LIQUID GLASS IPHONE ESTILO IOS 17+ (60 FPS SUAVE)
   ========================================================================== */

:root {
    /* Paleta de Colores Exclusiva Estilo iOS/Apple */
    --color-bg-dark: #08080c;
    --color-bg-deep: #0f0f15;
    
    /* Configuración de Cristaleria iOS (iPhone Glass Sheet) */
    --color-glass-base: rgba(22, 22, 32, 0.62); /* Cristal translúcido de alta legibilidad estilo iOS sheet */
    --color-glass-card: rgba(255, 255, 255, 0.035);
    --color-glass-card-hover: rgba(255, 255, 255, 0.065);
    --color-glass-border: rgba(255, 255, 255, 0.14); /* Borde de cristal fino */
    --color-glass-border-subtle: rgba(255, 255, 255, 0.08);
    --color-glass-highlight: rgba(255, 255, 255, 0.22);
    
    /* Colores del Sistema iOS */
    --ios-blue: #0a84ff; /* Azul brillante iOS Dark Mode */
    --ios-blue-rgb: 10, 132, 255;
    --ios-green: #30d158; /* Verde brillante */
    --ios-green-rgb: 48, 209, 88;
    --ios-red: #ff453a; /* Rojo brillante */
    --ios-red-rgb: 255, 69, 58;
    --ios-orange: #ff9f0a;
    --ios-purple: #bf5af2;
    --ios-teal: #64d2ff;
    
    /* Jerarquía de Textos */
    --text-primary: #ffffff;
    --text-secondary: #e5e5ed; /* Blanco titanio de alta lectura */
    --text-tertiary: #a1a1aa;
    
    /* Tipografía */
    --font-sf: 'Inter', -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", sans-serif;
    
    /* Gradientes */
    --gradient-blue: linear-gradient(135deg, #0a84ff, #00c6ff);
    --gradient-green: linear-gradient(135deg, #30d158, #61e185);
    --gradient-amber: linear-gradient(135deg, #ff9f0a, #ffd60a);
    
    /* Sombras Físicas Proyectadas */
    --shadow-premium: 0 30px 60px rgba(0, 0, 0, 0.45), inset 0 1px 0 rgba(255, 255, 255, 0.18);
    --shadow-card: 0 12px 28px rgba(0, 0, 0, 0.25), inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

/* ==========================================================================
   RESET & OPTIMIZACIONES DE RENDIMIENTO (HARDWARE ACCELERATION)
   ========================================================================== */

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

html {
    scroll-behavior: smooth;
    background-color: transparent;
}

/* Scrollbar Estilo macOS */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: var(--color-bg-dark);
}
::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    border: 2px solid var(--color-bg-dark);
}

body {
    font-family: var(--font-sf);
    color: var(--text-primary);
    background-color: transparent;
    line-height: 1.6;
    overflow-x: hidden;
    overflow-y: auto;
    position: relative;
    padding-bottom: 120px;
}

/* ==========================================================================
   FONDO ESTÁTICO: PLANTA NUCLEAR CON PARALLAX SUAVE (60 FPS)
   ========================================================================== */

.background-image-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -5;
    overflow: hidden;
    pointer-events: none;
    /* Promover a capa de composición de GPU */
    will-change: transform;
    transform: translate3d(0, 0, 0);
}

.background-image {
    position: absolute;
    top: -5%;
    left: -5%;
    width: 110%;
    height: 110%;
    background-size: cover;
    background-position: center 30%;
    background-repeat: no-repeat;
    background-image: url('assets/bg-1.jpg');
    
    /* Blur suave para que se vea la imagen */
    filter: blur(5px) brightness(0.92) saturate(1.20);
    
    /* Aceleración por hardware */
    will-change: transform;
    transform: translate3d(0, 0, 0);
    backface-visibility: hidden;
}

.background-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    /* Overlay cálido sutil: deja ver el fondo manteniendo legibilidad */
    background: radial-gradient(circle at 75% 18%, rgba(255, 185, 80, 0.25) 0%, transparent 50%),
                radial-gradient(circle at 30% 70%, rgba(10, 132, 255, 0.08) 0%, transparent 45%),
                linear-gradient(to bottom, rgba(8, 8, 12, 0.35) 0%, rgba(8, 8, 12, 0.80) 100%);
    z-index: 1;
}

/* GLOW CONTAINER OPTIMIZADO: Evita los filtros de blur animados que causaban lag.
   Utilizamos gradientes radiales estáticos muy ligeros que no sobrecargan la GPU */
.glow-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -4;
    overflow: hidden;
    pointer-events: none;
}

/* Tres auras de color premium sutiles aceleradas por GPU */
.blob {
    position: absolute;
    border-radius: 50%;
    opacity: 0.10;
    will-change: transform, opacity;
    transform: translate3d(0, 0, 0);
    filter: blur(120px);
    animation: pulseGlow 18s infinite alternate ease-in-out;
}

.blob-cyan {
    top: 15%;
    left: 8%;
    width: 380px;
    height: 380px;
    background: var(--ios-blue);
}

.blob-green {
    bottom: 25%;
    right: 8%;
    width: 420px;
    height: 420px;
    background: var(--ios-green);
    animation-delay: -6s;
}

.blob-purple {
    top: 55%;
    left: 50%;
    width: 320px;
    height: 320px;
    background: var(--ios-purple);
    animation-delay: -12s;
}

@keyframes pulseGlow {
    0% { transform: translate3d(0, 0, 0) scale(1); opacity: 0.06; }
    100% { transform: translate3d(40px, -40px, 0) scale(1.12); opacity: 0.14; }
}

/* ==========================================================================
   BARRA DE PROGRESO DE LECTURA (IPHONE STYLE)
   ========================================================================== */

.progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: rgba(255, 255, 255, 0.04);
    z-index: 10000;
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: var(--gradient-blue);
    box-shadow: 0 0 8px rgba(10, 132, 255, 0.6);
    transition: width 0.05s ease-out;
}

/* ==========================================================================
   MENÚ DE NAVEGACIÓN FLOTANTE (iOS PILL NAVIGATION)
   ========================================================================== */

.ios-navigation {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translate3d(-50%, 0, 0);
    z-index: 9999;
    width: 90%;
    max-width: 650px;
    /* Aceleración GPU */
    will-change: transform, opacity;
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.4s;
}

.ios-navigation.hidden {
    transform: translate3d(-50%, 100px, 0);
    opacity: 0;
}

.nav-pill-wrapper {
    /* Liquid Glass premium iOS 17+ - MÁS NOTORIO */
    background: rgba(12, 12, 22, 0.75);
    backdrop-filter: blur(40px) saturate(250%);
    -webkit-backdrop-filter: blur(40px) saturate(250%);
    border: 1px solid rgba(255, 255, 255, 0.32);
    border-radius: 40px;
    padding: 6px;
    display: flex;
    justify-content: space-around;
    align-items: center;
    box-shadow: 0 20px 45px rgba(0, 0, 0, 0.45), inset 0 1px 0 rgba(255, 255, 255, 0.15);
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-decoration: none;
    color: var(--text-tertiary);
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    padding: 6px 10px;
    border-radius: 30px;
    position: relative;
    cursor: pointer;
    flex: 1;
    min-width: 0;
}

.nav-item svg {
    margin-bottom: 2px;
    stroke: currentColor;
    transition: stroke 0.3s, transform 0.3s;
}

.nav-item span {
    font-size: 10px;
    font-weight: 500;
    letter-spacing: -0.01em;
    opacity: 0;
    height: 0;
    transition: opacity 0.2s, height 0.2s;
    white-space: nowrap;
    overflow: hidden;
}

.nav-item:hover {
    color: var(--text-primary);
}

.nav-item.active {
    color: var(--ios-blue);
    background: rgba(255, 255, 255, 0.1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.nav-item.active svg {
    transform: scale(1.08);
    stroke: var(--ios-blue);
}

.nav-item.active span {
    opacity: 1;
    height: 12px;
    margin-top: 1px;
}

/* ==========================================================================
   HEADER PRINCIPAL (HERO SECTION)
   ========================================================================== */

header {
    min-height: 95vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 80px 24px;
    text-align: center;
    position: relative;
    z-index: 10;
}

.header-glass-wrapper {
    /* Liquid Glass premium estilo iPhone 17 Pro - MÁS VISIBLE */
    background: rgba(12, 12, 22, 0.55);
    backdrop-filter: blur(35px) saturate(220%);
    -webkit-backdrop-filter: blur(35px) saturate(220%);
    border: 1px solid rgba(255, 255, 255, 0.28);
    border-radius: 40px;
    padding: 55px 35px;
    max-width: 860px;
    width: 100%;
    box-shadow: var(--shadow-premium);
    /* Animación de entrada suave */
    will-change: transform, opacity;
    animation: headerAppear 1s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes headerAppear {
    from {
        opacity: 0;
        transform: translate3d(0, 30px, 0) scale(0.96);
    }
    to {
        opacity: 1;
        transform: translate3d(0, 0, 0) scale(1);
    }
}

.header-badge {
    display: inline-flex;
    align-items: center;
    background: rgba(10, 132, 255, 0.12);
    border: 1px solid rgba(10, 132, 255, 0.3);
    color: var(--ios-blue);
    padding: 6px 14px;
    border-radius: 50px;
    font-size: 12.5px;
    font-weight: 600;
    letter-spacing: 0.01em;
    margin-bottom: 20px;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.pulse-indicator {
    width: 8px;
    height: 8px;
    background: var(--ios-blue);
    border-radius: 50%;
    margin-right: 8px;
    box-shadow: 0 0 8px var(--ios-blue);
    animation: glowIndicator 2s infinite ease-in-out;
}

@keyframes glowIndicator {
    0%, 100% { opacity: 0.5; }
    50% { opacity: 1; }
}

header h1 {
    font-size: clamp(2.3em, 5vw, 3.8em);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.035em;
    color: var(--text-primary);
    margin-bottom: 16px;
}

header p {
    font-size: clamp(1.05em, 1.8vw, 1.25em);
    color: var(--text-secondary);
    max-width: 680px;
    margin: 0 auto 28px;
    line-height: 1.65;
}

.scroll-prompt {
    display: flex;
    flex-direction: column;
    align-items: center;
    color: var(--text-tertiary);
    font-size: 13px;
    font-weight: 500;
}

.scroll-prompt span {
    margin-bottom: 6px;
}

.chevron-down {
    animation: bounceChevron 2.5s infinite ease-in-out;
}

@keyframes bounceChevron {
    0%, 100%, 20% { transform: translateY(0); }
    50% { transform: translateY(5px); }
}

/* ==========================================================================
   CONFORMACIÓN GENERAL DEL CONTENIDO (SECCIONES)
   ========================================================================== */

main {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 10;
}

.content-section {
    margin: 90px 0;
    padding: 50px 40px;
    
    /* Liquid Glass premium: cristal visible con backdrop-filter */
    background: rgba(15, 15, 25, 0.55);
    border: 1px solid rgba(255, 255, 255, 0.22);
    border-radius: 32px;
    
    /* Backdrop-filter más fuerte para glassmorphism notorio */
    backdrop-filter: blur(30px) saturate(200%);
    -webkit-backdrop-filter: blur(30px) saturate(200%);
    
    box-shadow: 0 35px 70px rgba(0, 0, 0, 0.50), inset 0 1px 0 rgba(255, 255, 255, 0.25);
    
    will-change: transform, opacity;
    transform: translate3d(0, 40px, 0);
    opacity: 0;
    transition: transform 0.8s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.content-section.revealed {
    opacity: 1;
    /* translate3d activa la aceleración por hardware */
    transform: translate3d(0, 0, 0);
}

.section-badge {
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ios-blue);
    margin-bottom: 12px;
}

.content-section h2 {
    font-size: clamp(1.8em, 4vw, 2.3em);
    font-weight: 700;
    letter-spacing: -0.025em;
    margin-bottom: 20px;
    line-height: 1.2;
}

.section-subtitle {
    font-size: 1.1em;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

/* ==========================================================================
   SECCIÓN 1: ¿QUÉ ES? & ÁTOMO INTERACTIVO
   ========================================================================== */

.glass-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 30px;
    align-items: center;
}

.lead-paragraph {
    font-size: 1.18em;
    color: var(--text-primary);
    font-weight: 500;
    margin-bottom: 16px;
    border-left: 3px solid var(--ios-blue);
    padding-left: 14px;
}

.glass-grid p {
    margin-bottom: 14px;
    color: var(--text-secondary);
    font-size: 1.05em;
}

/* Optimización de Átomo para evitar redibujados continuos complejos */
.glass-card-illustration {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 20px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 280px;
    position: relative;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.atom-container {
    width: 170px;
    height: 170px;
    position: relative;
    transform-style: preserve-3d;
    perspective: 400px;
    margin-bottom: 15px;
    will-change: transform;
}

.atom-nucleus {
    width: 22px;
    height: 22px;
    background: radial-gradient(circle, #ff453a 0%, #bf5af2 70%);
    border-radius: 50%;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 0 20px rgba(191, 90, 242, 0.6);
}

.atom-orbit {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 1px dashed rgba(100, 210, 255, 0.25);
    border-radius: 50%;
    transform-style: preserve-3d;
    will-change: transform;
}

.orbit-1 { transform: rotateX(70deg) rotateY(15deg); animation: rotateOrbit1 6s infinite linear; }
.orbit-2 { transform: rotateX(70deg) rotateY(135deg); animation: rotateOrbit2 6s infinite linear; }
.orbit-3 { transform: rotateX(70deg) rotateY(255deg); animation: rotateOrbit3 6s infinite linear; }

.electron {
    width: 8px;
    height: 8px;
    background: var(--ios-teal);
    border-radius: 50%;
    position: absolute;
    top: 0;
    left: 50%;
    transform: translate3d(-50%, 0, 0);
    box-shadow: 0 0 8px var(--ios-teal);
}

/* ==========================================================================
   SECCIÓN 2: ¿CÓMO SE PRODUCE? (FISIÓN Y FUSIÓN)
   ========================================================================== */

.production-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.glass-card {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 24px;
    padding: 30px;
    transition: all 0.35s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    overflow: hidden;
    will-change: transform, border-color, background-color;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(28px) saturate(200%);
    -webkit-backdrop-filter: blur(28px) saturate(200%);
}

.glass-card:hover {
    background: rgba(255, 255, 255, 0.095);
    border-color: rgba(255, 255, 255, 0.28);
    transform: translate3d(0, -4px, 0);
    box-shadow: 0 30px 60px rgba(0,0,0,0.45), inset 0 1px 0 rgba(255,255,255,0.28);
}

.card-icon {
    width: 54px;
    height: 54px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.fission-card .card-icon { background: rgba(255, 69, 58, 0.1); }
.fusion-card .card-icon { background: rgba(48, 209, 88, 0.1); }

.glass-card h3 {
    font-size: 1.4em;
    font-weight: 700;
    margin-bottom: 10px;
}

.pill-badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 30px;
    font-size: 10.5px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 16px;
}

.pill-danger { background: rgba(255, 69, 58, 0.15); color: #ff453a; border: 1.5px solid rgba(255, 69, 58, 0.3); }
.pill-success { background: rgba(48, 209, 88, 0.15); color: #30d158; border: 1.5px solid rgba(48, 209, 88, 0.3); }
.pill-info { background: rgba(10, 132, 255, 0.15); color: #64d2ff; border: 1.5px solid rgba(10, 132, 255, 0.3); }

.glass-card p {
    color: var(--text-secondary);
    font-size: 1em;
    line-height: 1.6;
    margin-bottom: 10px;
}

/* ==========================================================================
   SECCIÓN 3: FUNCIONAMIENTO & LÍNEA DE PROCESO
   ========================================================================== */

.process-timeline {
    position: relative;
    padding-left: 28px;
    margin-top: 30px;
}

.process-timeline::before {
    content: '';
    position: absolute;
    left: 10px;
    top: 10px;
    bottom: 10px;
    width: 2px;
    background: linear-gradient(to bottom, var(--ios-blue) 0%, var(--ios-purple) 50%, var(--ios-green) 100%);
    opacity: 0.3;
}

.timeline-step {
    position: relative;
    margin-bottom: 28px;
}

.timeline-step:last-child {
    margin-bottom: 0;
}

.step-number {
    position: absolute;
    left: -28px;
    top: 2px;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--color-bg-deep);
    border: 2px solid var(--ios-blue);
    color: var(--text-primary);
    font-size: 11px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2;
}

.step-content h4 {
    font-size: 1.15em;
    font-weight: 600;
    margin-bottom: 4px;
}

.step-content p {
    color: var(--text-secondary);
    font-size: 1em;
}



/* ==========================================================================
   SECCIÓN 4: PROS Y CONTRAS (EL GRAN DEBATE)
   ========================================================================== */

.pros-cons-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.glass-column {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 24px;
    padding: 30px 24px;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.column-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    padding-bottom: 12px;
}

.column-header h3 {
    font-size: 1.25em;
    font-weight: 700;
}

.pros-list li, .contras-list li {
    list-style: none;
    margin-bottom: 20px;
    position: relative;
    padding-left: 18px;
}

.pros-list li::before { content: '•'; color: var(--ios-green); font-size: 1.6em; position: absolute; left: 0; top: -5px; }
.contras-list li::before { content: '•'; color: var(--ios-red); font-size: 1.6em; position: absolute; left: 0; top: -5px; }

.highlight-title {
    font-size: 1.02em;
    font-weight: 600;
    color: var(--text-primary);
    display: block;
    margin-bottom: 3px;
}

.pros-list p, .contras-list p {
    font-size: 0.95em;
    color: var(--text-secondary);
}

/* ==========================================================================
   SECCIÓN 5: ACCIDENTES HISTÓRICOS (TIMELINE CARD LAYOUT)
   ========================================================================== */

.accidents-timeline {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.accident-card {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 20px;
    padding: 26px;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.accident-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 14px;
}

.accident-year {
    font-family: monospace;
    font-size: 1.35em;
    font-weight: 800;
    color: white;
    background: rgba(255, 255, 255, 0.08);
    padding: 2px 10px;
    border-radius: 6px;
}

.accident-severity {
    font-size: 9.5px;
    font-weight: 700;
    text-transform: uppercase;
    padding: 3px 8px;
    border-radius: 30px;
    letter-spacing: 0.04em;
}

.level-7 { background: rgba(255, 69, 58, 0.15); color: #ff453a; border: 1px solid rgba(255, 69, 58, 0.25); }
.level-6 { background: rgba(255, 159, 10, 0.15); color: #ff9f0a; border: 1px solid rgba(255, 159, 10, 0.25); }
.level-5 { background: rgba(191, 90, 242, 0.15); color: #bf5af2; border: 1px solid rgba(191, 90, 242, 0.25); }

.accident-card h3 {
    font-size: 1.25em;
    margin-bottom: 10px;
    font-weight: 700;
}

.accident-card p {
    font-size: 0.95em;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.accident-consequences {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--color-glass-border-subtle);
    border-radius: 10px;
    padding: 10px 14px;
    font-size: 12px;
}

/* ==========================================================================
   SECCIÓN 6: IMPACTO AMBIENTAL (BAR CHARTS CO2)
   ========================================================================== */

.co2-chart {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 18px;
    padding: 20px;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.chart-title {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-tertiary);
    display: block;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.chart-row {
    margin-bottom: 14px;
}

.chart-row:last-child {
    margin-bottom: 0;
}

.chart-row .lbl {
    font-size: 11.5px;
    font-weight: 500;
    color: var(--text-secondary);
    display: block;
    margin-bottom: 4px;
}

.bar-container {
    background: rgba(255,255,255,0.06);
    height: 20px;
    border-radius: 6px;
    overflow: hidden;
}

.bar {
    height: 100%;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding-right: 10px;
    font-size: 10px;
    font-weight: 700;
    color: white;
    font-family: monospace;
    will-change: width;
    transition: width 1s cubic-bezier(0.16, 1, 0.3, 1);
}

.bar-coal { background: var(--ios-red); }
.bar-gas { background: var(--ios-orange); }
.bar-solar { background: var(--ios-blue); }
.bar-nuclear { background: var(--ios-green); box-shadow: 0 0 8px rgba(48, 209, 88, 0.3); }

.chart-source {
    font-size: 10px;
    color: var(--text-tertiary);
    margin-top: 8px;
    text-align: right;
}

/* ==========================================================================
   SECCIÓN 7: USOS DE LA ENERGÍA NUCLEAR (GRID)
   ========================================================================== */

.uses-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.use-card {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 18px;
    padding: 24px;
    transition: all 0.35s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.use-card:hover {
    background: rgba(255, 255, 255, 0.095);
    border-color: rgba(255, 255, 255, 0.28);
    transform: translate3d(0, -3px, 0);
    box-shadow: 0 30px 60px rgba(0,0,0,0.45), inset 0 1px 0 rgba(255,255,255,0.28);
}

.use-icon {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid rgba(255, 255, 255, 0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 14px;
    color: var(--ios-blue);
}

.use-card h4 {
    font-size: 1.15em;
    font-weight: 600;
    margin-bottom: 6px;
}

.use-card p {
    font-size: 0.95em;
    color: var(--text-secondary);
}

/* ==========================================================================
   SECCIÓN 8: ¿QUÉ ES LA RADIACIÓN?
   ========================================================================== */

.radiation-comparison {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin: 24px 0;
}

.rad-box {
    border-radius: 18px;
    padding: 24px;
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.rad-box h4 {
    font-size: 1.15em;
    font-weight: 700;
    margin-bottom: 6px;
}

.rad-box p {
    font-size: 0.95em;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.rad-examples {
    font-size: 10.5px;
    font-weight: 600;
    color: var(--text-tertiary);
    background: rgba(0,0,0,0.15);
    padding: 6px 10px;
    border-radius: 8px;
    letter-spacing: 0.02em;
}

.interactive-radiation-visual {
    background: rgba(5, 5, 8, 0.65);
    border-radius: 18px;
    border: 1px solid rgba(255, 255, 255, 0.14);
    padding: 20px;
    margin-top: 24px;
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.interactive-instruction {
    font-size: 11px;
    font-weight: 600;
    color: var(--ios-blue);
    margin-bottom: 16px;
}

.penetration-board {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.penetration-row {
    display: flex;
    align-items: center;
    gap: 15px;
    cursor: pointer;
    padding: 8px;
    border-radius: 10px;
    transition: background 0.15s;
}

.penetration-row:hover {
    background: rgba(255, 255, 255, 0.02);
}

.particle-lbl {
    width: 70px;
    font-weight: 700;
    font-size: 12.5px;
}

.penetration-visual-path {
    flex: 1;
    height: 30px;
    background: rgba(255,255,255,0.02);
    border-radius: 6px;
    position: relative;
    display: flex;
    align-items: center;
}

.barrier {
    position: absolute;
    width: 50px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 9.5px;
    font-weight: 700;
    color: rgba(255,255,255,0.3);
    border-left: 2.5px solid rgba(255,255,255,0.15);
    background: rgba(255, 255, 255, 0.01);
}

.barrier-paper { left: 40%; }
.barrier-aluminum { left: 65%; }
.barrier-lead { left: 88%; width: calc(12% - 4px); }

.moving-ray {
    position: absolute;
    left: 4px;
    top: 50%;
    transform: translateY(-50%);
    height: 2px;
    width: 0%;
    border-radius: 1px;
    opacity: 0.8;
    will-change: width, opacity;
}

.moving-ray::after {
    content: '';
    position: absolute;
    right: 0;
    top: -3px;
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.alpha-ray { background: #ff453a; }
.alpha-ray::after { background: #ff453a; }
.beta-ray { background: #ff9f0a; }
.beta-ray::after { background: #ff9f0a; }
.gamma-ray { background: #30d158; }
.gamma-ray::after { background: #30d158; }

.moving-ray.firing {
    animation: fireRay 1.5s forwards linear;
}

.alpha-ray.firing { animation-name: fireRayAlpha; }
.beta-ray.firing { animation-name: fireRayBeta; }
.gamma-ray.firing { animation-name: fireRayGamma; }

@keyframes fireRayAlpha {
    0% { width: 0%; opacity: 1; }
    26% { width: 40%; opacity: 1; }
    27%, 100% { width: 40%; opacity: 0; }
}

@keyframes fireRayBeta {
    0% { width: 0%; opacity: 1; }
    51% { width: 65%; opacity: 1; }
    52%, 100% { width: 65%; opacity: 0; }
}

@keyframes fireRayGamma {
    0% { width: 0%; opacity: 1; }
    75% { width: 88%; opacity: 1; }
    76%, 100% { width: 88%; opacity: 0.1; }
}

/* ==========================================================================
   SECCIÓN 9: FUTURO (CARDS LAYOUT)
   ========================================================================== */

.future-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 20px;
}

.future-card {
    background: rgba(255, 255, 255, 0.055);
    border: 1px solid rgba(255, 255, 255, 0.14);
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(26px) saturate(190%);
    -webkit-backdrop-filter: blur(26px) saturate(190%);
}

.future-card h3 {
    font-size: 1.18em;
    font-weight: 700;
    margin-bottom: 10px;
}

.future-card p {
    font-size: 0.95em;
    color: var(--text-secondary);
}

/* ==========================================================================
   PIE DE PÁGINA (FOOTER)
   ========================================================================== */

footer {
    border-top: 1px solid var(--color-glass-border);
    background: var(--color-bg-deep);
    padding: 50px 20px;
    text-align: center;
    position: relative;
    z-index: 10;
}

.footer-content {
    max-width: 550px;
    margin: 0 auto;
}

.footer-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 1.05em;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-content p {
    font-size: 0.92em;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.footer-content p.copyright {
    color: var(--text-tertiary);
    font-size: 0.82em;
    margin-top: 12px;
}

.back-to-top {
    display: inline-block;
    margin-top: 20px;
    color: var(--ios-blue);
    text-decoration: none;
    font-size: 12.5px;
    font-weight: 600;
}

/* ==========================================================================
   RESPONSIVIDAD MÓVIL EXTREMA & OPTIMIZACIONES
   ========================================================================== */

@media (max-width: 1024px) {
    .content-section {
        padding: 35px 25px;
        margin: 70px 0;
    }
    
    .glass-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .production-grid, .pros-cons-container, .accidents-timeline, .uses-grid {
        grid-template-columns: 1fr;
    }
    
    .future-grid {
        grid-template-columns: 1fr;
    }
    
    /* Reducir blur en tablet para rendimiento */
    .content-section,
    .glass-card,
    .glass-card-illustration,
    .glass-column,
    .accident-card,
    .co2-chart,
    .use-card,
    .rad-box,
    .future-card,
    .interactive-radiation-visual {
        backdrop-filter: blur(16px) saturate(160%);
        -webkit-backdrop-filter: blur(16px) saturate(160%);
    }
}

@media (max-width: 768px) {
    header {
        padding: 60px 16px;
    }
    
    .header-glass-wrapper {
        padding: 40px 20px;
        border-radius: 28px;
    }
    
    .content-section {
        padding: 30px 20px;
        border-radius: 24px;
        margin: 50px 0;
    }
    
    /* Reducir blur en móvil para 60 FPS */
    .content-section,
    .glass-card,
    .glass-card-illustration,
    .glass-column,
    .accident-card,
    .co2-chart,
    .use-card,
    .rad-box,
    .future-card,
    .interactive-radiation-visual {
        backdrop-filter: blur(12px) saturate(150%);
        -webkit-backdrop-filter: blur(12px) saturate(150%);
    }
    
    .radiation-comparison {
        grid-template-columns: 1fr;
    }
    
    .ios-navigation {
        bottom: 16px;
    }
    
    .nav-pill-wrapper {
        padding: 5px;
    }
    
    .nav-item {
        padding: 4px 6px;
    }
    
    .nav-item span {
        font-size: 9px;
    }
}

@media (max-width: 480px) {
    .nav-item span {
        display: none;
    }
    
    .nav-pill-wrapper {
        justify-content: space-between;
    }
}