/* ============================================
   ATLAS METALS - Design System & Main Styles
   ============================================ */

/* --- CSS Variables --- */
:root {
    --color-bg: #0a0a0a;
    --color-bg-elevated: #141414;
    --color-bg-surface: #1a1a1a;
    --color-gold: #c8a45a;
    --color-gold-light: #e0c878;
    --color-gold-dark: #a8863a;
    --color-text: #f5f5f0;
    --color-text-muted: #8a8a80;
    --color-border: #2a2a2a;
    --color-overlay: rgba(10, 10, 10, 0.7);
    --color-overlay-heavy: rgba(10, 10, 10, 0.85);

    --font-heading: 'Cormorant Garamond', Georgia, serif;
    --font-body: 'DM Sans', 'Segoe UI', sans-serif;

    --fw-light: 300;
    --fw-regular: 400;
    --fw-medium: 500;
    --fw-semibold: 600;
    --fw-bold: 700;

    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    --spacing-2xl: 8rem;

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;

    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.6s ease;

    --max-width: 1200px;
    --max-width-narrow: 800px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-body);
    font-weight: var(--fw-regular);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

a:hover {
    color: var(--color-gold-light);
}

ul, ol {
    list-style: none;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: var(--fw-regular);
    line-height: 1.2;
    color: var(--color-text);
}

h1 {
    font-size: clamp(2.5rem, 6vw, 5rem);
    font-weight: var(--fw-light);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(2rem, 4vw, 3.5rem);
    font-weight: var(--fw-light);
    letter-spacing: -0.01em;
}

h3 {
    font-size: clamp(1.3rem, 2.5vw, 1.8rem);
    font-weight: var(--fw-regular);
}

h4 {
    font-size: clamp(1.1rem, 2vw, 1.3rem);
    font-weight: var(--fw-medium);
}

p {
    font-size: clamp(0.95rem, 1.2vw, 1.1rem);
    color: var(--color-text-muted);
    max-width: 65ch;
}

.text-gold {
    color: var(--color-gold);
}

.text-center {
    text-align: center;
}

/* --- Section Heading --- */
.section-label {
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: var(--fw-semibold);
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--color-gold);
    margin-bottom: var(--spacing-sm);
}

.section-title {
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    max-width: 600px;
}

.gold-line {
    width: 60px;
    height: 2px;
    background: var(--color-gold);
    margin: var(--spacing-md) 0;
}

.gold-line--center {
    margin-left: auto;
    margin-right: auto;
}

/* --- Container --- */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container--narrow {
    max-width: var(--max-width-narrow);
}

/* --- Sections --- */
section {
    padding: var(--spacing-xl) 0;
}

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

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

/* ============================================
   HEADER / NAVIGATION
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 1rem 0;
    background: linear-gradient(to bottom, rgba(10, 10, 10, 0.85) 0%, rgba(10, 10, 10, 0.4) 70%, transparent 100%);
    transition: background var(--transition-base), padding var(--transition-base);
}

.header--scrolled {
    background: rgba(10, 10, 10, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 0.6rem 0;
    border-bottom: 1px solid var(--color-border);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
}

.header__logo {
    display: flex;
    align-items: center;
    flex-shrink: 0;
    flex: 0 0 auto;
}

.header__logo img {
    height: 44px;
    width: auto;
    transition: height var(--transition-base);
}

.header--scrolled .header__logo img {
    height: 36px;
}

.nav {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    flex: 1 1 auto;
    justify-content: center;
}

.nav__list {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav__link {
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: var(--fw-medium);
    color: var(--color-text);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    position: relative;
    padding: 0.25rem 0;
    white-space: nowrap;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--color-gold);
    transition: width var(--transition-base);
}

.nav__link:hover,
.nav__link--active {
    color: var(--color-gold);
}

.nav__link:hover::after,
.nav__link--active::after {
    width: 100%;
}

.nav__lang {
    position: absolute;
    right: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.8rem;
    font-weight: var(--fw-semibold);
    color: var(--color-text);
    border: 1px solid rgba(245, 245, 240, 0.3);
    padding: 0.3rem 0.7rem;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.nav__lang:hover {
    color: var(--color-gold);
    border-color: var(--color-gold);
}

/* Hamburger */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: all var(--transition-base);
}

.hamburger--active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger--active span:nth-child(2) {
    opacity: 0;
}

.hamburger--active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding: 0;
}

.hero__bg {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.hero__bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        to bottom,
        rgba(10, 10, 10, 0.4) 0%,
        rgba(10, 10, 10, 0.6) 50%,
        rgba(10, 10, 10, 0.95) 100%
    );
}

.hero__content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 900px;
    padding: 0 var(--spacing-md);
}

.hero__title {
    margin-bottom: var(--spacing-md);
}

.hero__subtitle {
    font-size: clamp(1rem, 1.5vw, 1.25rem);
    color: var(--color-text-muted);
    margin: 0 auto var(--spacing-lg);
    max-width: 600px;
    line-height: 1.8;
}

.hero__scroll {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    color: var(--color-text-muted);
    font-size: 0.75rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

.hero__scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--color-gold), transparent);
    animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(0.6); }
    50% { opacity: 1; transform: scaleY(1); }
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: var(--fw-semibold);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding: 1rem 2.5rem;
    border: none;
    border-radius: 0;
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn--primary {
    background-color: var(--color-gold);
    color: var(--color-bg);
}

.btn--primary:hover {
    background-color: var(--color-gold-light);
    color: var(--color-bg);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(200, 164, 90, 0.3);
}

.btn--outline {
    background: transparent;
    color: var(--color-gold);
    border: 1px solid var(--color-gold);
}

.btn--outline:hover {
    background-color: var(--color-gold);
    color: var(--color-bg);
    transform: translateY(-2px);
}

.btn--ghost {
    background: transparent;
    color: var(--color-text);
    padding: 0.5rem 0;
    letter-spacing: 0.05em;
}

.btn--ghost::after {
    content: '→';
    transition: transform var(--transition-fast);
}

.btn--ghost:hover {
    color: var(--color-gold);
}

.btn--ghost:hover::after {
    transform: translateX(4px);
}

/* ============================================
   ABOUT SECTION
   ============================================ */
.about {
    padding: var(--spacing-2xl) 0;
}

.about__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.about__text p {
    margin-bottom: var(--spacing-sm);
}

.about__image {
    position: relative;
    aspect-ratio: 4/5;
    overflow: hidden;
}

.about__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.about__image::after {
    content: '';
    position: absolute;
    top: var(--spacing-md);
    left: var(--spacing-md);
    right: calc(var(--spacing-md) * -1);
    bottom: calc(var(--spacing-md) * -1);
    border: 1px solid var(--color-gold);
    z-index: -1;
    opacity: 0.3;
}

/* ============================================
   SERVICES SECTION
   ============================================ */
.services__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    align-items: stretch;
}

.service-card {
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    padding: var(--spacing-lg) var(--spacing-md);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--color-gold);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition-base);
}

.service-card:hover {
    border-color: var(--color-gold);
    transform: translateY(-4px);
}

.service-card:hover::before {
    transform: scaleX(1);
}

.service-card__icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-gold);
}

.service-card__title {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.service-card__text {
    font-size: 0.95rem;
    line-height: 1.7;
    flex-grow: 1;
}

/* ============================================
   PORTFOLIO / GALLERY
   ============================================ */
.portfolio__filters {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.filter-btn {
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: var(--fw-medium);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--color-text-muted);
    background: transparent;
    border: 1px solid var(--color-border);
    padding: 0.5rem 1.2rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.filter-btn:hover,
.filter-btn--active {
    color: var(--color-gold);
    border-color: var(--color-gold);
    background: rgba(200, 164, 90, 0.08);
}

.portfolio__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-sm);
}

.portfolio-item {
    position: relative;
    aspect-ratio: 1;
    overflow: hidden;
    cursor: pointer;
}

.portfolio-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.portfolio-item:hover img {
    transform: scale(1.08);
}

.portfolio-item__overlay {
    position: absolute;
    inset: 0;
    background: var(--color-overlay-heavy);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity var(--transition-base);
    padding: var(--spacing-sm);
}

.portfolio-item:hover .portfolio-item__overlay {
    opacity: 1;
}

.portfolio-item__title {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}

.portfolio-item__cat {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-gold);
}

/* Lightbox */
.lightbox {
    position: fixed;
    inset: 0;
    z-index: 2000;
    background: rgba(0, 0, 0, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-base);
}

.lightbox--active {
    opacity: 1;
    pointer-events: all;
}

.lightbox__content {
    max-width: 90vw;
    max-height: 85vh;
    position: relative;
}

.lightbox__content img {
    max-width: 100%;
    max-height: 80vh;
    object-fit: contain;
}

.lightbox__info {
    text-align: center;
    padding: var(--spacing-sm) 0;
}

.lightbox__title {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    color: var(--color-text);
}

.lightbox__desc {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-top: 0.25rem;
}

.lightbox__close {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    width: 44px;
    height: 44px;
    background: none;
    border: 1px solid var(--color-border);
    color: var(--color-text);
    font-size: 1.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    z-index: 2001;
}

.lightbox__close:hover {
    border-color: var(--color-gold);
    color: var(--color-gold);
}

.lightbox__nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 44px;
    height: 44px;
    background: none;
    border: 1px solid var(--color-border);
    color: var(--color-text);
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.lightbox__nav:hover {
    border-color: var(--color-gold);
    color: var(--color-gold);
}

.lightbox__nav--prev {
    left: 1.5rem;
}

.lightbox__nav--next {
    right: 1.5rem;
}

/* ============================================
   APPLICATIONS SECTION
   ============================================ */
.applications__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    align-items: stretch;
}

.application-card {
    position: relative;
    aspect-ratio: 3/4;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.application-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.application-card:hover img {
    transform: scale(1.05);
}

.application-card__content {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-lg) var(--spacing-md) var(--spacing-md);
    background: linear-gradient(to top, rgba(10, 10, 10, 0.9) 0%, transparent 100%);
}

.application-card__title {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}

.application-card__text {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* ============================================
   MATERIALS SECTION
   ============================================ */
.materials__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.materials__features {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.material-feature {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-start;
}

.material-feature__icon {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    border: 1px solid var(--color-gold);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gold);
    font-size: 1rem;
}

.material-feature__text h4 {
    margin-bottom: 0.25rem;
}

.material-feature__text p {
    font-size: 0.9rem;
}

.materials__gallery {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xs);
}

.materials__gallery img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

/* ============================================
   CTA SECTION
   ============================================ */
.cta {
    position: relative;
    padding: var(--spacing-2xl) 0;
    text-align: center;
    overflow: hidden;
}

.cta__bg {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    opacity: 0.15;
}

.cta .container {
    position: relative;
    z-index: 2;
}

.cta h2 {
    margin-bottom: var(--spacing-sm);
}

.cta p {
    margin: 0 auto var(--spacing-lg);
    max-width: 500px;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
    background-color: var(--color-bg-elevated);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-xl) 0 var(--spacing-md);
}

.footer__grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer__brand .header__logo img {
    height: 32px;
}

.footer__brand p {
    margin-top: var(--spacing-sm);
    font-size: 0.9rem;
}

.footer__title {
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: var(--fw-semibold);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-gold);
    margin-bottom: var(--spacing-sm);
}

.footer__links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer__links a {
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.footer__links a:hover {
    color: var(--color-text);
}

.footer__bottom {
    border-top: 1px solid var(--color-border);
    padding-top: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

/* ============================================
   CONTACT / QUOTE PAGE
   ============================================ */
.page-header {
    padding: calc(var(--spacing-2xl) + 80px) 0 var(--spacing-xl);
    text-align: center;
    background-color: var(--color-bg-elevated);
}

.contact__grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    padding: var(--spacing-xl) 0;
}

.contact__info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.contact-detail {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-start;
}

.contact-detail__icon {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    border: 1px solid var(--color-gold);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gold);
}

.contact-detail h4 {
    margin-bottom: 0.25rem;
}

.contact-detail p, .contact-detail a {
    font-size: 0.95rem;
    color: var(--color-text-muted);
}

/* Form */
.form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.form__group {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}

.form__row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
}

.form__label {
    font-size: 0.8rem;
    font-weight: var(--fw-medium);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
}

.form__label span {
    color: var(--color-gold);
}

.form__input,
.form__select,
.form__textarea {
    font-family: var(--font-body);
    font-size: 0.95rem;
    color: var(--color-text);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    padding: 0.9rem 1rem;
    transition: border-color var(--transition-fast);
    width: 100%;
}

.form__input:focus,
.form__select:focus,
.form__textarea:focus {
    outline: none;
    border-color: var(--color-gold);
}

.form__input::placeholder,
.form__textarea::placeholder {
    color: #555;
}

.form__select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238a8a80' stroke-width='1.5' fill='none'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    padding-right: 2.5rem;
    cursor: pointer;
}

.form__select option {
    background: var(--color-bg-elevated);
    color: var(--color-text);
}

.form__textarea {
    resize: vertical;
    min-height: 150px;
}

.form__submit {
    margin-top: var(--spacing-sm);
    align-self: flex-start;
}

.form__message {
    padding: var(--spacing-sm);
    font-size: 0.9rem;
    display: none;
}

.form__message--success {
    display: block;
    border: 1px solid var(--color-gold);
    color: var(--color-gold);
    background: rgba(200, 164, 90, 0.08);
}

.form__message--error {
    display: block;
    border: 1px solid #c85a5a;
    color: #c85a5a;
    background: rgba(200, 90, 90, 0.08);
}

/* ============================================
   MOBILE NAV OVERLAY
   ============================================ */
.mobile-nav {
    position: fixed;
    inset: 0;
    z-index: 999;
    background: var(--color-bg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-base);
}

.mobile-nav--active {
    opacity: 1;
    pointer-events: all;
}

.mobile-nav a {
    font-family: var(--font-heading);
    font-size: 2rem;
    color: var(--color-text);
    transition: color var(--transition-fast);
}

.mobile-nav a:hover {
    color: var(--color-gold);
}

/* ============================================
   SCROLL TO TOP
   ============================================ */
.scroll-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 44px;
    height: 44px;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    color: var(--color-gold);
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-base);
    z-index: 100;
}

.scroll-top--visible {
    opacity: 1;
    pointer-events: all;
}

.scroll-top:hover {
    background: var(--color-gold);
    color: var(--color-bg);
    border-color: var(--color-gold);
}

/* ============================================
   RESPONSIVE
   ============================================ */

/* Large tablet / small desktop */
@media (max-width: 1024px) {
    .about__grid,
    .materials__grid,
    .contact__grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .about__image {
        max-width: 500px;
        margin: 0 auto;
    }

    .about__image::after {
        display: none;
    }

    .services__grid,
    .applications__grid {
        grid-template-columns: 1fr 1fr;
    }

    .portfolio__grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer__grid {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-md);
    }

    .materials__gallery {
        max-width: 500px;
        margin: 0 auto;
    }
}

/* Tablet */
@media (max-width: 768px) {
    /* Navigation */
    .hamburger {
        display: flex;
    }

    .nav {
        display: none;
    }

    /* Spacing */
    section {
        padding: var(--spacing-lg) 0;
    }

    .about {
        padding: var(--spacing-xl) 0;
    }

    /* Hero */
    .hero {
        min-height: 100svh;
    }

    .hero__content {
        padding: 0 var(--spacing-sm);
    }

    .hero__title {
        font-size: clamp(2rem, 8vw, 3.5rem);
    }

    .hero__subtitle {
        font-size: 1rem;
        line-height: 1.6;
        padding: 0 0.5rem;
    }

    .hero__scroll {
        bottom: 1.5rem;
    }

    /* Grids to single column */
    .services__grid,
    .applications__grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .portfolio__grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.5rem;
    }

    /* Service cards */
    .service-card {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    /* Application cards - horizontal on tablet */
    .application-card {
        aspect-ratio: 16/9;
    }

    /* Portfolio overlay always visible on touch */
    .portfolio-item__overlay {
        opacity: 1;
        background: linear-gradient(to top, rgba(10, 10, 10, 0.85) 0%, transparent 60%);
        justify-content: flex-end;
        padding-bottom: var(--spacing-sm);
    }

    .portfolio-item__title {
        font-size: 1rem;
    }

    .portfolio-item__cat {
        font-size: 0.65rem;
    }

    /* Filters scrollable */
    .portfolio__filters {
        justify-content: flex-start;
        overflow-x: auto;
        flex-wrap: nowrap;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        padding-bottom: 0.5rem;
    }

    .portfolio__filters::-webkit-scrollbar {
        display: none;
    }

    .filter-btn {
        white-space: nowrap;
        flex-shrink: 0;
    }

    /* Form */
    .form__row {
        grid-template-columns: 1fr;
    }

    .form__submit {
        align-self: stretch;
        text-align: center;
    }

    /* Contact page */
    .page-header {
        padding: calc(var(--spacing-xl) + 70px) var(--spacing-sm) var(--spacing-lg);
    }

    .contact__grid {
        padding: var(--spacing-lg) 0;
    }

    /* Footer */
    .footer__grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .footer__bottom {
        flex-direction: column;
        gap: var(--spacing-sm);
        text-align: center;
    }

    /* Lightbox */
    .lightbox__content {
        max-width: 95vw;
        padding: 0 0.5rem;
    }

    .lightbox__content img {
        max-height: 70vh;
    }

    .lightbox__close {
        top: 0.75rem;
        right: 0.75rem;
        width: 40px;
        height: 40px;
        background: rgba(10, 10, 10, 0.8);
    }

    .lightbox__nav {
        width: 36px;
        height: 36px;
        background: rgba(10, 10, 10, 0.8);
    }

    .lightbox__nav--prev {
        left: 0.5rem;
    }

    .lightbox__nav--next {
        right: 0.5rem;
    }

    .lightbox__title {
        font-size: 1.2rem;
    }

    /* CTA */
    .cta {
        padding: var(--spacing-xl) 0;
    }

    /* Materials gallery */
    .materials__gallery img {
        height: 160px;
    }

    /* Scroll to top */
    .scroll-top {
        bottom: 1rem;
        right: 1rem;
        width: 40px;
        height: 40px;
    }

    /* Buttons */
    .btn {
        padding: 0.85rem 2rem;
        font-size: 0.8rem;
        width: 100%;
        justify-content: center;
    }

    .btn--ghost {
        width: auto;
    }
}

/* Small mobile */
@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    .container {
        padding: 0 var(--spacing-sm);
    }

    /* Hero fine-tuning */
    .hero__title {
        font-size: clamp(1.8rem, 9vw, 2.8rem);
    }

    .hero__subtitle {
        font-size: 0.9rem;
    }

    .section-label {
        font-size: 0.7rem;
    }

    /* Portfolio 2 column stays but tighter */
    .portfolio__grid {
        gap: 4px;
    }

    .portfolio-item__title {
        font-size: 0.85rem;
    }

    .portfolio-item__cat {
        font-size: 0.6rem;
    }

    /* Mobile nav text */
    .mobile-nav a {
        font-size: 1.6rem;
    }

    /* Applications single column */
    .applications__grid {
        gap: 0.5rem;
    }

    .application-card__title {
        font-size: 1.1rem;
    }

    /* Header */
    .header__logo img {
        height: 32px;
    }

    .header--scrolled .header__logo img {
        height: 28px;
    }

    /* Section headings */
    h2 {
        font-size: clamp(1.6rem, 6vw, 2.5rem);
    }

    /* Contact details */
    .contact-detail__icon {
        width: 38px;
        height: 38px;
    }

    /* Material features */
    .material-feature__icon {
        width: 34px;
        height: 34px;
    }

    /* Footer */
    .footer {
        padding: var(--spacing-lg) 0 var(--spacing-sm);
    }
}

/* Very small mobile (iPhone SE etc) */
@media (max-width: 360px) {
    html {
        font-size: 13px;
    }

    .hero__title {
        font-size: 1.6rem;
    }

    .portfolio__grid {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .portfolio-item {
        aspect-ratio: 4/3;
    }
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {
    /* Always show overlay on touch devices */
    .portfolio-item__overlay {
        opacity: 1;
        background: linear-gradient(to top, rgba(10, 10, 10, 0.8) 0%, transparent 50%);
        justify-content: flex-end;
        padding-bottom: var(--spacing-sm);
    }

    /* Disable hover effects on service cards */
    .service-card:hover {
        transform: none;
    }

    .service-card::before {
        transform: scaleX(1);
    }

    /* Bigger touch targets */
    .filter-btn {
        padding: 0.6rem 1.4rem;
        min-height: 44px;
    }

    .nav__lang {
        min-height: 44px;
        display: flex;
        align-items: center;
    }

    /* Application cards no zoom on tap */
    .application-card:hover img {
        transform: none;
    }

    /* Lightbox swipe area bigger */
    .lightbox__nav {
        width: 50px;
        height: 80px;
    }
}

/* Landscape mobile */
@media (max-height: 500px) and (orientation: landscape) {
    .hero {
        min-height: 100svh;
    }

    .hero__title {
        font-size: 2rem;
    }

    .hero__subtitle {
        font-size: 0.85rem;
        margin-bottom: var(--spacing-md);
    }

    .hero__scroll {
        display: none;
    }
}