.header {
    position: sticky;
    top: 0;
    z-index: var(--z-dropdown);
    
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.25rem;
    
    background: var(--surface-primary);
    backdrop-filter: blur(1.25rem) saturate(180%);
    border-bottom: 0.0625rem solid var(--border-medium);
    box-shadow: var(--shadow-md);
    height: 4.5rem;
    transition: var(--transition-normal);
}

body.dark .header {
    background: rgba(20, 20, 20, 0.85);
    border-bottom-color: var(--border-strong);
}

.hd-p-logo {
    margin: 0;
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 50%;
    transition: var(--transition-fast);
    letter-spacing: -0.03125rem;
}

.hd-p-logo:hover {
    filter: brightness(1.2) drop-shadow(0 0 0.625rem var(--color-primary));
}

.hd-bn-modos,
.hd-bn-hamburguesa {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.75rem;
    height: 2.75rem;
    border: 0.125rem solid var(--border-medium);
    border-radius: var(--radius-lg);
    background: var(--surface-secondary);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: 1.25rem;
    padding: 0;
    flex-shrink: 0;
    overflow: hidden;
}

body.dark .hd-bn-modos,
body.dark .hd-bn-hamburguesa {
    background: var(--surface-hover);
    border-color: var(--border-strong);
}

.hd-bn-modos::before,
.hd-bn-hamburguesa::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    opacity: 0;
    transition: var(--transition-fast);
    z-index: -1;
}

.hd-bn-modos:hover::before,
.hd-bn-hamburguesa:hover::before {
    opacity: 1;
}

.hd-bn-modos:hover,
.hd-bn-hamburguesa:hover {
    color: var(--text-inverse);
    border-color: transparent;
    transform: translateY(-0.125rem);
    box-shadow: var(--shadow-lg), 0 0 1.25rem rgba(99, 102, 241, 0.4);
}

body.dark .hd-bn-modos:hover,
body.dark .hd-bn-hamburguesa:hover {
    box-shadow: var(--shadow-lg), 0 0 1.25rem rgba(129, 140, 248, 0.5);
}

.hd-bn-modos:active,
.hd-bn-hamburguesa:active {
    transform: scale(0.92);
}

.hd-bn-modos-sun,
.hd-bn-modos-moon {
    transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.hd-bn-modos-sun {
    display: block;
}

.hd-bn-modos-moon {
    display: none;
}

body.dark .hd-bn-modos-sun {
    display: none;
}

body.dark .hd-bn-modos-moon {
    display: block;
}

.hd-bn-modos:hover .hd-bn-modos-sun,
.hd-bn-modos:hover .hd-bn-modos-moon {
    transform: rotate(180deg) scale(1.1);
}

.hd-bn-hamburguesa .bi-list {
    display: block;
    transition: transform 0.3s ease;
}

.hd-bn-hamburguesa .bi-x-lg {
    display: none;
    transition: transform 0.3s ease;
}

.hd-bn-hamburguesa.activo .bi-list {
    display: none;
}

.hd-bn-hamburguesa.activo .bi-x-lg {
    display: block;
    animation: rotateIn 0.3s ease;
}

@keyframes rotateIn {
    from {
        transform: rotate(-90deg);
        opacity: 0;
    }
    to {
        transform: rotate(0);
        opacity: 1;
    }
}

.hd-nav {
    position: fixed;
    top: 4.8rem;
    left: 0;
    right: 0;
    background: var(--surface-primary);
    backdrop-filter: blur(1.25rem);
    border-bottom: 0.125rem solid var(--border-medium);
    box-shadow: var(--shadow-xl);
    
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
    opacity: 0;
}

body.dark .hd-nav {
    background: rgba(20, 20, 20, 0.95);
    border-bottom-color: var(--border-strong);
}

.hd-nav.nav-abierto {
    max-height: calc(100vh - 4.5rem);
    opacity: 1;
    overflow-y: auto;
}

.hd-nav-ul {
    list-style: none;
    margin: 0;
    padding: 1.25rem 0;
}

.hd-nav-ul-li {
    position: relative;
}

.hd-nav-ul-li-a {
    position: relative;
    display: block;
    padding: 1rem 1.5rem;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
    font-size: var(--font-size-base);
    transition: var(--transition-fast);
    overflow: hidden;
}

.hd-nav-ul-li-a::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 0.25rem;
    background: linear-gradient(180deg, var(--color-primary), var(--color-accent));
    transform: scaleY(0);
    transition: transform 0.3s ease;
}

.hd-nav-ul-li-a::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, var(--color-primary-light), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.hd-nav-ul-li-a:hover::before {
    transform: scaleY(1);
}

.hd-nav-ul-li-a:hover::after {
    opacity: 0.1;
}

.hd-nav-ul-li-a:hover {
    color: var(--color-primary);
    padding-left: 2rem;
}

body.dark .hd-nav-ul-li-a:hover {
    color: var(--color-primary-light);
}

.submenu {
    list-style: none;
    margin: 0;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    background: var(--surface-secondary);
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), padding 0.3s ease;
    border-left: 0.125rem solid var(--border-light);
}

body.dark .submenu {
    background: var(--bg-tertiary);
    border-left-color: var(--border-medium);
}

.submenu.submenu-abierto {
    max-height: 37.5rem;
    padding: 0.75rem 0;
}

.submenu a {
    display: flex;
    align-items: center;
    padding: 0.75rem 1.5rem 0.75rem 2.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: var(--transition-fast);
    position: relative;
}

.submenu a::before {
    content: '→';
    position: absolute;
    left: 1.5rem;
    opacity: 0;
    transform: translateX(-0.5rem);
    transition: all 0.3s ease;
    color: var(--color-accent);
}

.submenu a:hover::before {
    opacity: 1;
    transform: translateX(0);
}

.submenu a:hover {
    background: var(--surface-hover);
    color: var(--color-primary);
    padding-left: 3rem;
}

body.dark .submenu a:hover {
    color: var(--color-primary-light);
}

@media (min-width: 48rem) {
    .header {
        padding: 1rem 2.5rem;
    }

    .hd-p-logo {
        font-size: 1.5rem;
        max-width: 60%;
    }

    .hd-bn-hamburguesa {
        display: none;
    }

    .hd-nav {
        position: static;
        max-height: none;
        opacity: 1;
        overflow: visible;
        background: transparent;
        border: none;
        box-shadow: none;
        backdrop-filter: none;
    }

    .hd-nav-ul {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        padding: 0;
    }

    .hd-nav-ul-li-a {
        padding: 0.75rem 1.25rem;
        border-radius: var(--radius-lg);
    }

    .hd-nav-ul-li-a::before {
        display: none;
    }

    .hd-nav-ul-li-a::after {
        border-radius: var(--radius-lg);
    }

    .hd-nav-ul-li-a:hover {
        background: var(--surface-hover);
        padding-left: 1.25rem;
        transform: translateY(-0.125rem);
    }

    .submenu {
        position: absolute;
        top: calc(100% + 0.2rem);
        left: 0;
        min-width: 15rem;
        background: var(--surface-primary);
        border: 0.125rem solid var(--border-medium);
        border-radius: var(--radius-lg);
        box-shadow: var(--shadow-xl);
        max-height: 0;
        padding: 0;
        overflow: hidden;
        transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        opacity: 0;
        transform: translateY(-0.625rem);
        border-left: 0.125rem solid var(--border-medium);
    }

    body.dark .submenu {
        background: var(--surface-secondary);
        border-color: var(--border-strong);
        box-shadow: var(--shadow-xl), 0 0 1.25rem rgba(0, 0, 0, 0.5);
    }

    .hd-nav-ul-li:hover .submenu {
        max-height: 37.5rem;
        padding: 0.75rem;
        opacity: 1;
        transform: translateY(0);
    }

    .submenu a {
        padding: 0.75rem 1rem;
        border-radius: var(--radius-md);
        margin-bottom: 0.25rem;
    }

    .submenu a:last-child {
        margin-bottom: 0;
    }

    .submenu a::before {
        left: 0.5rem;
    }

    .submenu a:hover {
        background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
        color: var(--text-inverse);
        padding-left: 2rem;
    }

    body.dark .submenu a:hover {
        color: var(--text-inverse);
    }
}

@media (min-width: 64rem) {
    .header {
        padding: 1.25rem 4rem;
    }

    .hd-p-logo {
        font-size: 1.75rem;
        max-width: none;
    }

    .hd-bn-modos {
        width: 3rem;
        height: 3rem;
        font-size: 1.375rem;
    }

    .hd-nav-ul {
        gap: 1rem;
    }

    .hd-nav-ul-li-a {
        padding: 0.875rem 1.5rem;
        font-size: var(--font-size-lg);
    }

    .hd-nav-ul-li-a:hover {
        padding-left: 1.5rem;
    }

    .submenu {
        min-width: 17.5rem;
    }

    .submenu a {
        font-size: var(--font-size-base);
    }
}

@media (min-width: 90rem) {
    .header {
        padding: 1.5rem 6rem;
    }

    .hd-p-logo {
        font-size: 2rem;
    }

    .hd-nav-ul {
        gap: 1.5rem;
    }

    .hd-nav-ul-li-a {
        padding: 1rem 2rem;
    }

    .hd-nav-ul-li-a:hover {
        padding-left: 2rem;
    }
}