/* VARIABLES */
:root {
--color-bg: #f5f7fb;
--color-bg-start: #f7f9fc;
--color-surface: #ffffff;
--color-surface-soft: #eef3f9;
--color-text: #132238;
--color-text-muted: #5c6b7d;
--color-border: #d8e0ea;
--color-primary: #1d4ed8;
--color-primary-strong: #0f3d91;
--color-accent: #14b8a6;
--color-shadow: rgba(15, 23, 42, 0.08);
--color-shadow-strong: rgba(15, 23, 42, 0.16);
--color-contrast: #ffffff;
}

/* BODY */
body {
font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
margin: 0;
background: var(--color-bg);
color: var(--color-text);
}

body:has(#temaToggle:checked) {
--color-bg: #0b1220;
--color-bg-start: #09101c;
--color-surface: #111827;
--color-surface-soft: #172033;
--color-text: #e5eefb;
--color-text-muted: #9fb0c3;
--color-border: #24324a;
--color-primary: #60a5fa;
--color-primary-strong: #93c5fd;
--color-accent: #2dd4bf;
--color-shadow: rgba(0, 0, 0, 0.28);
--color-shadow-strong: rgba(0, 0, 0, 0.4);
}

.contenedor-principal {
max-width: 1200px;
min-height: 100vh;
margin: 0 auto;
padding: clamp(12px, 2vw, 24px);
box-sizing: border-box;
background: linear-gradient(180deg, var(--color-bg-start) 0%, var(--color-bg) 100%);
color: var(--color-text);
}

.tema-checkbox {
position: absolute;
width: 1px;
height: 1px;
padding: 0;
margin: -1px;
overflow: hidden;
clip: rect(0, 0, 0, 0);
white-space: nowrap;
border: 0;
}

/* HEADER */
.barra-navegacion {
display: flex;
justify-content: space-between;
align-items: center;
gap: 20px;
padding: 18px 24px;
margin-bottom: 30px;
background-color: var(--color-surface);
border-radius: 14px;
box-shadow: 0 10px 25px var(--color-shadow);
border: 1px solid var(--color-border);
}

.marca {
display: flex;
align-items: center;
gap: 14px;
}

.logo {
display: flex;
align-items: center;
justify-content: center;
width: 56px;
height: 56px;
border-radius: 50%;
background: linear-gradient(135deg, var(--color-primary-strong), var(--color-primary));
color: var(--color-contrast);
font-weight: 700;
font-size: 0.85rem;
letter-spacing: 0.05em;
}

.marca-texto h1 {
font-size: 1.2rem;
margin: 0 0 4px;
color: var(--color-primary-strong);
}

.marca-texto p {
margin: 0;
color: var(--color-text-muted);
font-size: 0.95rem;
}

/* NAV */
.navegacion-superior {
display: flex;
align-items: center;
gap: 18px;
flex-wrap: wrap;
}

.navegacion-superior a {
text-decoration: none;
color: var(--color-text);
font-weight: 600;
padding: 10px 14px;
border-radius: 999px;
transition: background-color 0.3s ease, color 0.3s ease, transform 0.2s ease;
}

.navegacion-superior a:hover {
background-color: var(--color-primary);
color: var(--color-contrast);
transform: translateY(-1px);
}

.navegacion-superior a:focus-visible {
outline: 3px solid var(--color-accent);
outline-offset: 2px;
}

.tema-toggle {
display: inline-flex;
align-items: center;
justify-content: space-between;
gap: 12px;
min-height: 44px;
padding: 4px 0;
font: inherit;
font-weight: 700;
color: var(--color-text);
cursor: pointer;
user-select: none;
}

.tema-toggle__texto {
font-size: 0.92rem;
white-space: nowrap;
}

.tema-toggle__interruptor {
position: relative;
display: inline-flex;
align-items: center;
flex-shrink: 0;
width: 58px;
height: 32px;
padding: 4px;
border-radius: 999px;
background: linear-gradient(180deg, var(--color-surface-soft), var(--color-surface));
border: 1px solid var(--color-border);
box-shadow: inset 0 1px 2px var(--color-shadow);
transition: background-color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.tema-toggle__interruptor::before {
content: "";
display: block;
width: 22px;
height: 22px;
border-radius: 50%;
background: linear-gradient(135deg, var(--color-primary-strong), var(--color-primary));
box-shadow: 0 4px 10px var(--color-shadow-strong);
transform: translateX(0);
transition: transform 0.3s ease, background-color 0.3s ease, box-shadow 0.3s ease;
}

.tema-toggle:hover .tema-toggle__interruptor {
border-color: var(--color-primary);
}

.tema-checkbox:focus-visible ~ .contenedor-principal .tema-toggle__interruptor {
outline: 3px solid var(--color-accent);
outline-offset: 3px;
}

.tema-checkbox:checked ~ .contenedor-principal .tema-toggle__interruptor::before {
transform: translateX(26px);
}

/* MAIN */
.seccion-central {
padding: 8px 0 24px;
}

.contacto {
margin-top: 40px;
padding: 22px 24px;
background-color: var(--color-surface);
border-radius: 12px;
border: 1px solid var(--color-border);
box-shadow: 0 4px 6px -1px var(--color-shadow);
position: relative;
z-index: 1;
}

.contacto h2 {
margin: 0 0 8px;
color: var(--color-primary-strong);
}

.contacto p {
margin: 0;
color: var(--color-text-muted);
}

/* TARJETAS */
.grid-proyectos {
display: grid;
grid-template-columns: repeat(4, 1fr);
gap: clamp(16px, 2vw, 25px);
align-items: stretch;
margin-bottom: 16px;
}

.tarjeta {
background-color: var(--color-surface);
padding: 30px;
border-radius: 12px;
text-align: center;
border: 1px solid var(--color-border);
box-shadow: 0 4px 6px -1px var(--color-shadow);
will-change: transform, background-color, box-shadow;
transition:
transform 0.3s ease,
box-shadow 0.3s ease,
background-color 0.3s ease;
}

.tarjeta h3 {
color: var(--color-primary-strong);
font-size: 1.2rem;
line-height: 1.25;
font-weight: 800;
margin: 0 0 10px;
}

.tarjeta-subtitulo {
color: var(--color-accent);
font-size: 0.92rem;
font-weight: 700;
line-height: 1.35;
margin: 0 0 12px;
text-transform: uppercase;
letter-spacing: 0.04em;
}

.tarjeta p:last-child {
color: inherit;
font-size: 0.98rem;
line-height: 1.6;
margin: 0;
}

.tarjeta:hover {
transform: translateY(-8px);
box-shadow: 0 16px 30px -10px var(--color-shadow-strong);
background-color: var(--color-surface-soft);
cursor: pointer;
}

/* ==========================================
RESPONSIVE DESIGN (MEDIA QUERIES)
========================================== */

/* TABLETS */
@media (max-width: 992px) {
.grid-proyectos {
grid-template-columns: repeat(2, 1fr);
}
}

/* CELULARES */
@media (max-width: 600px) {
.contenedor-principal {
padding: 10px;
}

.barra-navegacion {
flex-direction: column;
align-items: flex-start;
padding: 16px;
}

.marca {
width: 100%;
}

.navegacion-superior {
width: 100%;
flex-direction: column;
align-items: stretch;
gap: 10px;
}

.navegacion-superior a {
width: 100%;
text-align: center;
}

.tema-toggle {
width: 100%;
}

.grid-proyectos {
grid-template-columns: repeat(1, 1fr);
}
}