:root {
    --bg: #0b0b0d;
    --card: #ffffff;
    --text: #111;
    --muted: rgba(17, 17, 17, .65);
    --line: rgba(17, 17, 17, .10);
    --brand: #316d9d;
    --brand2: #3572a7;
    --shadow: 0 18px 40px rgba(0, 0, 0, .10);
    --shadow2: 0 10px 25px rgba(0, 0, 0, .08);
    --radius: 18px;
    --radius2: 14px;
    --max: 1100px;
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
}

body {
    font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
    color: var(--text);
    background: #f6f7fb;
    overflow-x: hidden;
}

a {
    color: inherit;
    text-decoration: none;
}

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


/* =========================
   HEADER + NAV
========================= */

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(11, 11, 13, .86);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, .10);
}

.header-inner {
    max-width: var(--max);
    margin: 0 auto;
    padding: .85rem 1.1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.hamburger {
    display: none;
    font-size: 1.35rem;
    line-height: 1;
    color: #fff;
    background: rgba(255, 255, 255, .08);
    border: 1px solid rgba(255, 255, 255, .14);
    border-radius: 12px;
    padding: .55rem .65rem;
    cursor: pointer;
    transition: transform 160ms ease, background 160ms ease;
}

.hamburger:hover {
    transform: translateY(-1px);
    background: rgba(255, 255, 255, .11);
}

.brand {
    display: flex;
    align-items: center;
    gap: .85rem;
    min-width: 240px;
}

.brand-logo {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    object-fit: cover;
}

.brand-text {
    line-height: 1.1;
}

.brand-name {
    color: #fff;
    font-weight: 800;
    letter-spacing: .2px;
    font-size: 1.05rem;
}

.brand-sub {
    color: rgba(255, 255, 255, .75);
    font-size: .85rem;
    margin-top: .15rem;
}

.sponsor {
    background: rgba(11, 11, 13, .86);
    padding: .3rem .5rem;
    border-radius: 12px;
}

.sponsor img {
    width: 120px;
    opacity: .95;
}


/* =========================
   NAV
========================= */

.nav-menu {
    max-width: var(--max);
    margin: 0 auto;
    padding: .2rem 1.1rem .9rem;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: .9rem;
    flex-wrap: wrap;
    justify-content: center;
    margin: 0;
    padding: 0;
}

.nav-links a {
    color: rgba(255, 255, 255, .88);
    font-weight: 650;
    font-size: .95rem;
    padding: .45rem .7rem;
    border-radius: 999px;
    border: 1px solid transparent;
    transition: background 160ms ease, border-color 160ms ease, transform 160ms ease, color 160ms ease;
}

.nav-links a:hover {
    transform: translateY(-1px);
    background: rgba(255, 255, 255, .08);
    border-color: rgba(255, 255, 255, .12);
    color: #fff;
}

.nav-links a.active {
    background: rgba(49, 109, 157, .22);
    border-color: rgba(49, 109, 157, .35);
    color: #fff;
}


/* =========================
   HERO
========================= */

.hero {
    position: relative;
    height: 62vh;
    min-height: 420px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.hero-img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-dim {
    position: absolute;
    inset: 0;
    background: radial-gradient(900px 420px at 50% 25%, rgba(49, 109, 157, .45), transparent 60%), linear-gradient(to bottom, rgba(0, 0, 0, .32), rgba(0, 0, 0, .65));
}

.hero-text {
    position: relative;
    z-index: 2;
    padding: 0 1.2rem;
    color: #fff;
    max-width: 760px;
}

.hero-text h2 {
    margin: 0 0 .5rem;
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 800;
    letter-spacing: -0.02em;
}

.hero-text p {
    margin: 0;
    font-size: 1.08rem;
    color: rgba(255, 255, 255, .88);
}


/* =========================
   ABOUT / LESSONS SECTION
========================= */

.about-section {
    padding: 3.2rem 1.1rem 4rem;
}

.about-content {
    max-width: 820px;
    margin: 0 auto;
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow2);
    padding: 2rem 2rem 2.1rem;
    position: relative;
    overflow: hidden;
}

.about-content::before {
    content: "";
    position: absolute;
    inset: 0 0 auto 0;
    height: 6px;
    background: linear-gradient(135deg, var(--brand), var(--brand2));
}

.about-content h3 {
    margin: 0 0 1rem;
    font-size: 1.75rem;
    letter-spacing: -0.01em;
}

.about-content ul {
    margin: 0 0 1.35rem;
    padding-left: 1.2rem;
}

.about-content li {
    margin: .8rem 0;
    line-height: 1.55;
    color: var(--text);
    font-size: 1.02rem;
}

.about-content li strong {
    color: var(--brand);
}

.about-content p {
    margin: 0;
    font-size: 1rem;
    color: var(--text);
    padding-top: 1rem;
    border-top: 1px solid var(--line);
}

.about-content p strong {
    color: var(--brand);
}


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

footer {
    background: #0b0b0d;
    border-top: 1px solid rgba(255, 255, 255, .08);
    padding: 1.4rem 1rem;
    text-align: center;
}

footer p {
    margin: 0;
    color: rgba(255, 255, 255, .75);
    font-size: .95rem;
}


/* =========================
   MOBILE NAV
========================= */

@media (max-width: 860px) {
    .hamburger {
        display: inline-flex;
    }
    .nav-menu {
        display: none;
        padding-top: .4rem;
    }
    .nav-menu.active {
        display: block;
    }
    .nav-links {
        flex-direction: column;
        align-items: flex-start;
        justify-content: flex-start;
        padding-top: .4rem;
    }
    .nav-links a {
        width: 100%;
    }
    .brand {
        min-width: 0;
        flex: 1;
    }
    .brand-sub {
        font-size: .78rem;
    }
    .sponsor img {
        width: 95px;
    }
}


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

@media (max-width: 700px) {
    .hero {
        height: 54vh;
        min-height: 360px;
    }
    .hero-text h2 {
        font-size: clamp(2rem, 8vw, 2.8rem);
    }
    .hero-text p {
        font-size: 1rem;
    }
    .about-content {
        padding: 1.5rem 1.2rem 1.6rem;
    }
    .about-content h3 {
        font-size: 1.45rem;
    }
    .about-content li {
        font-size: .98rem;
    }
}

@media (max-width: 520px) {
    .header-inner {
        padding: .8rem .85rem;
    }
    .nav-menu {
        padding-left: .85rem;
        padding-right: .85rem;
        padding-bottom: .8rem;
    }
    .hero {
        min-height: 320px;
    }
    .hero-img {
        object-position: center;
    }
    .about-section {
        padding: 2.3rem .85rem 3rem;
    }
}