/* ==========================================================================
   ÍSTALOS - INDUSTRIAL TECHNOLOGY SYSTEM (CSS3 VARS & RESET)
   ========================================================================== */

:root {
    /* Paleta Cromática Corporativa */
    --color-primary: #101D30;      /* Azul Marino */
    --color-accent: #9B6013;       /* Bronze Industrial */
    --color-accent-hover: #7A4B0F;
    --color-steel: #B2BCC4;        /* Acero Inoxidable */
    --color-graphite: #252B33;     /* Grafito */
    --color-bg-light: #F2F5F8;     /* Gris claro fondo */
    --color-white: #FFFFFF;
    --color-text: #5F6B7A;         /* Gris de texto */
    --color-text-dark: #1A232E;

    /* Tipografía Fluid Design */
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --fs-sm: clamp(0.8rem, 0.17vw + 0.76rem, 0.89rem);
    --fs-base: clamp(1rem, 0.34vw + 0.91rem, 1.19rem);
    --fs-h3: clamp(1.25rem, 0.61vw + 1.1rem, 1.58rem);
    --fs-h2: clamp(1.75rem, 1.21vw + 1.45rem, 2.42rem);
    --fs-h1: clamp(2.25rem, 2.18vw + 1.7rem, 3.44rem);

    /* UI Measurements */
    --max-width: 1240px;
    --radius-sm: 4px;
    --radius-md: 8px;
    --transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
    --shadow-md: 0 4px 20px rgba(16, 29, 48, 0.08);
}

/* CSS Reset & Accessibility Improvements */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-family: var(--font-main);
    font-size: 16px;
    color: var(--color-text);
    background-color: var(--color-white);
}

body {
    line-height: 1.6;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--color-accent-hover);
}

/* Accessible Focus Styles */
:focus-visible {
    outline: 3px solid var(--color-accent);
    outline-offset: 3px;
}

/* Layout Utilities */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section-padding {
    padding: 5rem 0;
}

.bg-dark {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.bg-light {
    background-color: var(--color-bg-light);
}

/* Typography Helpers */
h1, h2, h4 {
    color: var(--color-primary);
    font-weight: 700;
    line-height: 1.2;
}

h3 {
    color: var(--color-accent);
    font-weight: 700;
    line-height: 1.2;
}

.bg-dark h1, .bg-dark h2, .bg-dark h3 {
    color: var(--color-white);
}

h1 { font-size: var(--fs-h1); }
h2 { font-size: var(--fs-h2); margin-bottom: 1rem; }
h3 { font-size: var(--fs-h3); margin-bottom: 0.75rem; }

.section-title {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 3.5rem auto;
}

.section-title .badge {
    display: inline-block;
    color: var(--color-accent);
    font-size: var(--fs-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: 0.5rem;
}

/* Buttons Component */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.85rem 1.75rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    gap: 0.5rem;
}

.btn-primary {
    background-color: var(--color-accent);
    color: var(--color-white);
}

.btn-primary:hover {
    background-color: var(--color-accent-hover);
    color: var(--color-white);
}

.btn-secondary {
    background-color: transparent;
    border-color: var(--color-steel);
    color: var(--color-white);
}

.btn-secondary:hover {
    background-color: var(--color-white);
    color: var(--color-primary);
}

/* Header & Navigation */
.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: rgba(16, 29, 48, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid rgba(178, 188, 196, 0.2);
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-accent);
    letter-spacing: 2px;
}

.logo span {
    color: var(--color-accent);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
    list-style: none;
}

.nav-link {
    color: var(--color-steel);
    font-weight: 500;
}

.nav-link:hover, .nav-link.active {
    color: var(--color-white);
    border-bottom: 2px solid var(--color-accent);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--color-white);
    font-size: 1.8rem;
    cursor: pointer;
}

/* Industrial Grid Systems */
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 2rem; align-items: center; }
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

/* Cards Component */
.card {
    background: var(--color-white);
    border: 1px solid rgba(178, 188, 196, 0.3);
    border-radius: var(--radius-md);
    padding: 2rem;
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-accent);
}

/* Footer Component */
.footer {
    background-color: var(--color-graphite);
    color: var(--color-steel);
    padding: 4rem 0 2rem 0;
    border-top: 3px solid var(--color-accent);
}

.footer-bottom {
    margin-top: 3rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(178, 188, 196, 0.1);
    text-align: center;
    font-size: var(--fs-sm);
}

.demo-badge {
    display: inline-block;
    background: #FFF3CD;
    color: #856404;
    font-size: 0.75rem;
    padding: 0.2rem 0.5rem;
    border-radius: 3px;
    font-weight: bold;
    margin-bottom: 0.5rem;
}