*, *::before, *::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    overflow-x: hidden;
}

/* ─── Navbar ─── */
#site-header {
    background: transparent;
    transition: background 0.3s ease, box-shadow 0.3s ease, backdrop-filter 0.3s ease;
}

#site-header.scrolled {
    background: rgba(6, 12, 24, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 1px 0 rgba(45, 212, 191, 0.05), 0 4px 30px rgba(0, 0, 0, 0.3);
}

.nav-link {
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1.5px;
    background: #2dd4bf;
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

/* ─── Buttons ─── */
.btn-primary {
    background: linear-gradient(135deg, #0d9488 0%, #14b8a6 50%, #2dd4bf 100%);
    color: #fff;
    border: none;
    border-radius: 0.75rem;
    padding: 0.875rem 2rem;
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    box-shadow: 0 4px 20px rgba(13, 148, 136, 0.3);
}

.btn-primary:hover {
    background: linear-gradient(135deg, #0f766e 0%, #0d9488 50%, #14b8a6 100%);
    box-shadow: 0 8px 30px rgba(13, 148, 136, 0.4);
    transform: translateY(-2px);
    color: #fff;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: #e2e8f0;
    border: 1px solid rgba(148, 163, 184, 0.2);
    border-radius: 0.75rem;
    padding: 0.875rem 2rem;
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(45, 212, 191, 0.3);
    color: #2dd4bf;
}

/* ─── Input Fields ─── */
.input-field {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid rgba(148, 163, 184, 0.15);
    border-radius: 0.75rem;
    padding: 0.875rem 1rem;
    color: #e2e8f0;
    font-family: 'Inter', sans-serif;
    font-size: 0.9375rem;
    transition: all 0.2s ease;
    outline: none;
    width: 100%;
}

.input-field::placeholder {
    color: #64748b;
}

.input-field:hover {
    border-color: rgba(148, 163, 184, 0.3);
}

.input-field:focus {
    border-color: #2dd4bf;
    box-shadow: 0 0 0 3px rgba(45, 212, 191, 0.1);
    background: rgba(15, 23, 42, 0.8);
}

.input-field:invalid:not(:placeholder-shown) {
    border-color: #ef4444;
}

/* ─── Service Cards ─── */
.card-service {
    opacity: 1;
}

/* ─── Testimonial Cards ─── */
.card-testimonial {
    opacity: 1;
}

/* ─── FAQ ─── */
.faq-item {
    opacity: 1;
}

.faq-toggle {
    font-family: 'Inter', sans-serif;
}

.faq-icon {
    transition: transform 0.3s ease, border-color 0.3s ease;
}

.faq-toggle[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
    border-color: #2dd4bf;
}

.faq-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-content.open {
    max-height: 200px;
    padding-top: 0;
    padding-bottom: 0;
}

/* ─── Back to Top ─── */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: rgba(13, 148, 136, 0.9);
    border: 1px solid rgba(45, 212, 191, 0.3);
    color: #fff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    z-index: 50;
    box-shadow: 0 4px 20px rgba(13, 148, 136, 0.3);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: rgba(13, 148, 136, 1);
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(13, 148, 136, 0.4);
}

/* ─── Mobile Menu ─── */
#mobile-menu {
    animation: slideDown 0.3s ease;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#mobile-menu.open {
    display: block;
}

#mobile-menu.hidden {
    display: none;
}

.mobile-nav-link {
    font-family: 'Inter', sans-serif;
}

/* ─── Hamburger ─── */
.hamburger-line {
    transition: all 0.3s ease;
}

#mobile-menu-btn.active .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

#mobile-menu-btn.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

#mobile-menu-btn.active .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(4px, -4px);
    width: 1.25rem;
}

/* ─── Scroll Reveal ─── */
.reveal {
    opacity: 1;
    transform: none;
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.revealed {
    opacity: 1;
    transform: none;
}

/* ─── Reduced Motion ─── */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    html {
        scroll-behavior: auto;
    }
    .reveal {
        opacity: 1;
        transform: none;
    }
    .back-to-top {
        transition: none;
    }
}

/* ─── Responsive ─── */
@media (max-width: 767px) {
    .font-serif {
        font-size: clamp(1.75rem, 8vw, 2.5rem);
    }
}