/* ==========================================================================
   TechBiz Security — main.css
   Reset, base typography, layout, header, footer, nav.
   ========================================================================== */

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

* { margin: 0; padding: 0; }

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
    scroll-padding-top: calc(var(--header-h) + 12px);
}

body {
    font-family: var(--font-body);
    background: var(--bg);
    color: var(--text);
    line-height: 1.65;
    font-size: 16px;
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

a {
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition);
}
a:hover { color: var(--accent-2); }

h1, h2, h3, h4, h5 {
    font-family: var(--font-head);
    font-weight: 700;
    line-height: 1.15;
    color: var(--text);
    letter-spacing: 0.5px;
}
h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
h2 { font-size: clamp(1.8rem, 4vw, 2.6rem); }
h3 { font-size: clamp(1.3rem, 2.5vw, 1.7rem); }

p { color: var(--text-secondary); }

ul { list-style: none; }

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
    border-radius: 4px;
}

::selection { background: var(--accent); color: var(--text-on-accent); }

/* --------------------------------------------------------------------------
   Layout
   -------------------------------------------------------------------------- */
.container {
    width: 100%;
    max-width: var(--container);
    margin-inline: auto;
    padding-inline: clamp(1rem, 4vw, 2rem);
}

.section { padding-block: clamp(3rem, 8vw, var(--space-6)); }

.section__head {
    text-align: center;
    max-width: 720px;
    margin: 0 auto var(--space-5);
}
.section__eyebrow {
    font-family: var(--font-head);
    font-size: 0.8rem;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: var(--accent);
    display: inline-block;
    margin-bottom: var(--space-1);
}
.section__head p { margin-top: var(--space-2); }

.grid { display: grid; gap: var(--space-3); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

.text-gradient {
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.mt { margin-top: var(--space-3); }

/* --------------------------------------------------------------------------
   Header / Nav
   -------------------------------------------------------------------------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-h);
    display: flex;
    align-items: center;
    background: color-mix(in srgb, var(--bg) 70%, transparent);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
}
.site-header.is-scrolled {
    border-bottom-color: var(--border);
    background: color-mix(in srgb, var(--bg) 88%, transparent);
}
.site-header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: var(--text);
    font-family: var(--font-head);
    font-weight: 900;
    font-size: 1.15rem;
    letter-spacing: 0.5px;
}
.brand__mark { width: 36px; height: 36px; display: grid; place-items: center; }
.brand__mark svg { width: 36px; height: 36px; }
.brand__accent { color: var(--accent); margin-left: 2px; }

.main-nav__list { display: flex; align-items: center; gap: clamp(0.5rem, 1.6vw, 1.6rem); }
.main-nav__list a {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 6px 2px;
    position: relative;
}
.main-nav__list a:hover,
.main-nav__list a[aria-current="page"] { color: var(--text); }
.main-nav__list a::after {
    content: "";
    position: absolute;
    left: 0; bottom: -2px;
    width: 0; height: 2px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    transition: width var(--transition);
}
.main-nav__list a:hover::after,
.main-nav__list a[aria-current="page"]::after { width: 100%; }
.main-nav__cta a::after { display: none; }

.header-actions { display: flex; align-items: center; gap: var(--space-2); }

.theme-toggle {
    width: 42px; height: 42px;
    display: grid; place-items: center;
    border: 1px solid var(--border);
    border-radius: 50%;
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    font-size: 1rem;
}
.theme-toggle:hover { border-color: var(--border-strong); box-shadow: 0 0 14px var(--glow); }
:root[data-theme="dark"] .theme-toggle__light { display: none; }
:root[data-theme="light"] .theme-toggle__dark { display: none; }

.nav-toggle {
    display: none;
    width: 42px; height: 42px;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    background: none;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    padding: 0 10px;
}
.nav-toggle span {
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: transform var(--transition), opacity var(--transition);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.site-footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    margin-top: var(--space-6);
}
.site-footer__grid {
    display: grid;
    grid-template-columns: 1.4fr 1fr 1fr 1.4fr;
    gap: var(--space-4);
    padding-block: var(--space-5);
}
.site-footer__col h4 {
    font-family: var(--font-head);
    font-size: 0.95rem;
    letter-spacing: 1px;
    margin-bottom: var(--space-2);
    color: var(--text);
}
.site-footer__col ul li { margin-bottom: 0.55rem; }
.site-footer__col a { color: var(--text-secondary); font-size: 0.92rem; }
.site-footer__col a:hover { color: var(--accent); }
.site-footer__tag { color: var(--accent); font-family: var(--font-head); margin: var(--space-2) 0 0.5rem; font-size: 0.9rem; }
.site-footer__desc { font-size: 0.9rem; }
.site-footer__contact i,
.site-footer__offices i { color: var(--accent); width: 18px; }
.site-footer__offices li { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 0.55rem; }

.site-footer__bottom { border-top: 1px solid var(--border); }
.site-footer__bottom-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: var(--space-2);
    padding-block: var(--space-3);
}
.site-footer__bottom p { font-size: 0.85rem; }
.site-footer__legal { display: flex; gap: var(--space-3); }
.site-footer__legal a { font-size: 0.85rem; color: var(--text-secondary); }

.back-to-top {
    position: fixed;
    right: 22px; bottom: 92px;
    width: 46px; height: 46px;
    border-radius: 50%;
    border: 1px solid var(--border-strong);
    background: var(--surface-solid);
    color: var(--accent);
    cursor: pointer;
    display: grid; place-items: center;
    opacity: 0;
    transform: translateY(20px);
    pointer-events: none;
    transition: opacity var(--transition), transform var(--transition);
    z-index: 90;
}
.back-to-top.is-visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.back-to-top:hover { box-shadow: 0 0 18px var(--glow); }

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
    .grid--4 { grid-template-columns: repeat(2, 1fr); }
    .site-footer__grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
    .nav-toggle { display: flex; }
    .main-nav {
        position: fixed;
        inset: var(--header-h) 0 auto 0;
        background: var(--bg-secondary);
        border-bottom: 1px solid var(--border);
        transform: translateY(-120%);
        transition: transform var(--transition);
        padding: var(--space-3);
        max-height: calc(100vh - var(--header-h));
        overflow-y: auto;
    }
    .main-nav.is-open { transform: translateY(0); }
    .main-nav__list { flex-direction: column; align-items: stretch; gap: 0.25rem; }
    .main-nav__list li { border-bottom: 1px solid var(--border); }
    .main-nav__list a { display: block; padding: 0.9rem 0.25rem; }
    .main-nav__cta { padding-top: var(--space-2); }
    .main-nav__cta a { display: block; text-align: center; }
    .grid--2, .grid--3 { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .grid--4 { grid-template-columns: 1fr; }
    .site-footer__grid { grid-template-columns: 1fr; }
    .site-footer__bottom-inner { flex-direction: column; text-align: center; }
}