/* ================================
   GLOBAL RESET & BASE
================================== */

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: #050608;
    color: #d0d3db;
    font-family: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
    line-height: 1.6;
}

/* Links */
a {
    color: #4da6ff;
    text-decoration: none;
}

a:hover {
    color: #ffffff;
}

/* ================================
   CENTERED HEADER & NAVIGATION
================================== */

.site-header {
    background-color: #0a0c10;
    padding: 20px;
    text-align: center;
    border-bottom: 1px solid #15161a;
    position: sticky;
    top: 0;
    z-index: 20;
}

.logo {
    color: #ffffff;
    font-size: 23px;
    font-weight: bold;
    margin: 0 auto;
    text-align: center;
    letter-spacing: 0.05em;
}

/* Main nav */
.main-nav {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 18px;
    margin-top: 12px;
}

.nav-item {
    position: relative;
}

/* Nav links */
.nav-link {
    color: #ffffff;
    font-size: 15px;
    padding-bottom: 4px;
    border-bottom: 2px solid transparent;
}

.nav-link:hover {
    color: #4da6ff;
}

.nav-link.active {
    border-bottom: 2px solid #4da6ff;
    color: #4da6ff;
}

/* Dropdown menus */
.dropdown-menu {
    display: none;
    position: absolute;
    top: 28px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #0f1116;
    border: 1px solid #2a2d36;
    border-radius: 6px;
    min-width: 220px;
    z-index: 1000;
}

.dropdown-menu a {
    display: block;
    padding: 10px 14px;
    color: #d0d3db;
    font-size: 14px;
}

.dropdown-menu a:hover {
    background-color: #1a1d24;
    color: #4da3ff;
}

.dropdown:hover .dropdown-menu {
    display: block;
}

/* ================================
   HERO / BANNER CAROUSEL
================================== */

.hero {
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px 20px 10px;
}

.banner {
    position: relative;
    overflow: hidden;
    border-radius: 10px;
    border: 1px solid #1a1b20;
    background: #080910;
    height: 220px;
}

.banner-slide {
    position: absolute;
    inset: 0;
    padding: 26px 28px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.7s ease;
}

.banner-slide.active {
    opacity: 1;
}

.banner-title {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 8px;
}

.banner-sub {
    font-size: 14px;
    color: #c0c3cc;
    max-width: 520px;
    line-height: 1.6;
}

.banner-cta {
    margin-top: 16px;
    display: inline-block;
    padding: 8px 14px;
    border-radius: 4px;
    border: 1px solid #2b6cff;
    color: #e5ecff;
    font-size: 13px;
}

.banner-dots {
    position: absolute;
    bottom: 12px;
    right: 16px;
    display: flex;
    gap: 6px;
}

.banner-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #3a3c46;
    cursor: pointer;
}

.banner-dot.active {
    background: #4da6ff;
}

/* ================================
   BRAND BLOCK
================================== */

.brand-block {
    margin-top: 26px;
}

.brand-title {
    font-size: 26px;
    font-weight: 650;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.brand-sub {
    margin-top: 6px;
    font-size: 14px;
    color: #c0c3cc;
    max-width: 620px;
}

/* ================================
   DUAL IMAGES GRID
================================== */

.dual-images {
    margin-top: 28px;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
}

.dual-images img {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 10px;
    border: 1px solid #181920;
    background: #050608;
}

.dual-caption {
    font-size: 12px;
    color: #a7abb7;
    margin-top: 6px;
}

/* ================================
   COGNITIVE THREADS
================================== */

.threads-section {
    margin-top: 30px;
}

.threads-title {
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: #8a8e9a;
    margin-bottom: 10px;
}

.threads-strip {
    display: flex;
    overflow-x: auto;
    gap: 10px;
    padding-bottom: 6px;
}

.thread-chip {
    white-space: nowrap;
    font-size: 12px;
    padding: 6px 10px;
    border-radius: 999px;
    border: 1px solid #262833;
    background: #090a10;
    color: #d5d7e0;
    flex: 0 0 auto;
}

/* ================================
   ENGINEERING TOOLS GRID
================================== */

.section {
    max-width: 1100px;
    margin: 0 auto;
    padding: 10px 20px 30px;
}

.section-title {
    font-size: 16px;
    font-weight: 600;
    margin-top: 30px;
    margin-bottom: 10px;
}

.section-sub {
    font-size: 13px;
    color: #b3b7c2;
    max-width: 620px;
    margin-bottom: 14px;
}
.content {
    max-width: 1000px;
    margin: 40px auto;
    padding: 0 20px;
    line-height: 1.6;
}
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 12px;
}

.tool-link {
    display: block;
    padding: 14px 14px 12px;
    border-radius: 8px;
    border: 1px solid #1a1b22;
    background: #070810;
}

.tool-link:hover {
    border-color: #2f5fe0;
}

.tool-title {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 4px;
}

.tool-meta {
    font-size: 12px;
    color: #a7abb7;
}

/* ================================
   HOLLOW PHYSICS FEATURE
================================== */

.hp-feature {
    margin-top: 26px;
    padding: 18px 18px 16px;
    border-radius: 8px;
    border: 1px solid #1b1c24;
    background: #080910;
}

.hp-tag {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.14em;
    color: #8a8e9a;
    margin-bottom: 4px;
}

.hp-title {
    font-size: 15px;
    font-weight: 600;
}

.hp-sub {
    font-size: 13px;
    color: #c0c3cc;
    margin-top: 4px;
}

.hp-cta {
    display: inline-block;
    margin-top: 10px;
    font-size: 12px;
    color: #4da6ff;
}

/* ================================
   FOOTER
================================== */

.site-footer {
    margin-top: 60px;
    padding: 40px 20px;
    background-color: #0a0c10;
    text-align: center;
    color: #7a7f8a;
    font-size: 14px;
    border-top: 1px solid #1a1d24;
}

.footer-buttons {
    margin-bottom: 25px;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px;
}

.footer-btn {
    display: inline-block;
    padding: 8px 16px;
    background-color: #0f1116;
    border: 1px solid #2a2d36;
    border-radius: 6px;
    color: #4da3ff;
    font-size: 14px;
}

.footer-btn:hover {
    background-color: #1a1d24;
    border-color: #4da3ff;
}

.footer-contact p {
    margin: 8px 0;
    line-height: 1.5;
}

.footer-copy {
    margin-top: 25px;
    color: #5f6570;
}

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

@media (max-width: 992px) {
    .content {
        margin: 30px auto;
    }
}

@media (max-width: 768px) {

    .main-nav {
        gap: 12px;
    }

    .dual-images {
        grid-template-columns: 1fr;
    }

    .banner {
        height: auto;
        min-height: 220px;
    }

    .footer-buttons {
        flex-direction: column;
        align-items: center;
    }

    .footer-btn {
        width: 100%;
        max-width: 280px;
    }
}

@media (max-width: 480px) {

    .logo {
        font-size: 18px;
    }

    .nav-link {
        font-size: 13px;
    }

    .brand-title {
        font-size: 20px;
    }

    .content {
        padding: 0 14px;
    }
}