:root {
    --yuta-blue: #00aeff;
    --yuta-dark: #001546;
    --bg-black: #0d0d0d;
}

body {
    font-family: 'Montserrat', sans-serif;
    background-color: var(--bg-black);
    color: #ffffff;
    overflow-x: hidden;
    font-weight: 300;
}

p {
    text-align: justify;
}

.text-center p { text-align: center; }
.text-left p   { text-align: left; }
.text-right p  { text-align: right; }

.glass-nav {
    background: rgba(13, 13, 13, 0.9);
    backdrop-filter: blur(15px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.text-gradient {
    background: linear-gradient(to bottom, #ffffff 30%, #a1a1aa 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.floating-fiber {
    position: absolute;
    background: linear-gradient(90deg, transparent, var(--yuta-blue), transparent);
    height: 1px;
    pointer-events: none;
    animation: drift linear infinite;
    opacity: 0.2;
}

@keyframes drift {
    from { transform: translateX(-100%) translateY(0) rotate(-2deg); opacity: 0; }
    50% { opacity: 0.3; }
    to { transform: translateX(200%) translateY(30px) rotate(2deg); opacity: 0; }
}

.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 1s cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

.material-card {
    transition: all 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    border: 1px solid rgba(255, 255, 255, 0.03);
    background: #111;
}

.material-card:hover {
    border-color: var(--yuta-blue);
    background: rgba(0, 174, 255, 0.02);
    box-shadow: 0 10px 40px -10px rgba(0, 174, 255, 0.1);
}

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

.logo-container img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* Language Toggle System */
html[lang="en"] .lang-bg { display: none !important; }
html[lang="bg"] .lang-en { display: none !important; }

/* Multi-level Dropdown Nav */
.nav-item { position: relative; }
.nav-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
}
.nav-item:hover > .nav-dropdown { display: block; }
.nav-subitem { position: relative; }
.nav-subdropdown {
    display: none;
    position: absolute;
    top: 0;
    left: 100%;
}
.nav-subitem:hover > .nav-subdropdown { display: block; }
.nav-link {
    display: block;
    padding: 10px 16px;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: #9ca3af;
    transition: color 0.2s, background 0.2s;
    white-space: nowrap;
}
.nav-link:hover {
    color: var(--yuta-blue);
    background: rgba(255, 255, 255, 0.05);
}
.nav-subitem-trigger {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 16px;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: #9ca3af;
    cursor: default;
    transition: color 0.2s, background 0.2s;
    white-space: nowrap;
}
.nav-subitem:hover > .nav-subitem-trigger {
    color: var(--yuta-blue);
    background: rgba(255, 255, 255, 0.05);
}

/* ── Mobile Navigation ─────────────────────────────────────────────────── */

.mobile-hamburger {
    display: flex;
    align-items: center;
    color: white;
    padding: 0.5rem;
    cursor: pointer;
    background: none;
    border: none;
}
@media (min-width: 1024px) {
    .mobile-hamburger { display: none; }
}

.mobile-nav-overlay {
    position: fixed;
    inset: 0;
    z-index: 60;
    background: var(--bg-black);
    opacity: 0;
    pointer-events: none;
    transition: opacity 200ms ease;
    overflow-y: auto;
}
.mobile-nav-overlay.is-open {
    opacity: 1;
    pointer-events: auto;
}

body.mobile-nav-open {
    overflow: hidden;
}

.mobile-nav-inner {
    min-height: 100%;
    display: flex;
    flex-direction: column;
    padding: 6rem 2rem 3rem;
}

.mobile-close-btn {
    position: fixed;
    top: 1.5rem;
    right: 2rem;
    color: white;
    padding: 0.5rem;
    cursor: pointer;
    z-index: 61;
    background: none;
    border: none;
}

.mobile-nav-links {
    flex: 1;
    display: flex;
    flex-direction: column;
}

/* Top-level plain links (HOME, HISTORY) */
.mobile-nav-link {
    display: block;
    padding: 1rem 0;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.7);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: color 0.2s;
}
.mobile-nav-link:hover,
.mobile-nav-link.is-active {
    color: var(--yuta-blue);
}

/* Nested links inside accordions */
.mobile-nav-link--nested {
    font-size: 10px;
    padding: 0.75rem 0 0.75rem 1rem;
    color: #6b7280;
    border-bottom: none;
}
.mobile-nav-link--nested:hover,
.mobile-nav-link--nested.is-active {
    color: var(--yuta-blue);
}

/* Top-level accordion (PRODUCTS, SERVICES, APPLICATIONS) */
.mobile-accordion-trigger {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 1rem 0;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.7);
    border: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: color 0.2s, border-color 0.2s;
    cursor: pointer;
    background: none;
}
.mobile-accordion-trigger.is-open {
    color: white;
    border-bottom-color: transparent;
}
.mobile-accordion-trigger .mobile-chevron {
    transition: transform 300ms ease;
    flex-shrink: 0;
}
.mobile-accordion-trigger.is-open .mobile-chevron {
    transform: rotate(180deg);
}

.mobile-accordion-panel {
    max-height: 0;
    overflow: hidden;
    transition: max-height 300ms ease;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}
.mobile-accordion-panel.is-open {
    max-height: 1000px;
}

/* Sub-accordion (VATEX, YUTALIN) */
.mobile-sub-accordion-trigger {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 0.75rem 0 0.75rem 1rem;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: #6b7280;
    transition: color 0.2s;
    cursor: pointer;
    background: none;
    border: none;
}
.mobile-sub-accordion-trigger.is-open {
    color: rgba(255, 255, 255, 0.7);
}
.mobile-sub-accordion-trigger .mobile-sub-chevron {
    transition: transform 300ms ease;
    flex-shrink: 0;
}
.mobile-sub-accordion-trigger.is-open .mobile-sub-chevron {
    transform: rotate(180deg);
}

.mobile-sub-accordion-panel {
    max-height: 0;
    overflow: hidden;
    transition: max-height 300ms ease;
}
.mobile-sub-accordion-panel.is-open {
    max-height: 200px;
}

/* Language switcher at bottom of overlay */
.mobile-nav-lang {
    padding-top: 2rem;
    display: flex;
    justify-content: flex-start;
}