:root {
    --background: #F8FAFC;
    --surface: #FFFFFF;
    --primary: #2563EB;
    --primary-dark: #1D4ED8;
    --text: #0F172A;
    --text-light: #64748B;
    --shadow: rgba(15,23,42,.08);
    --radius: 16px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Inter", sans-serif;
    background-color: var(--background);
    color: var(--text);
}

.container {
    width: min(92%, 1280px);
    margin: 0 auto;
}

.site-header {
    background: var(--surface);
    border-bottom: 1px solid #e2e8f0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.site-header h1 {
    margin: 0;
    font-size: 42px;
}

.site-header p {
    margin-top: 8px;
    font-size: 18px;
    color: #d9e2ec;
}

.nav-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 85px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 16px;
}

.logo-icon {
    width: 52px;
    height: 52px;
    background: var(--primary);
    color: white;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: bold;
}

.logo h1 {
    margin: 0;
    font-size: 28px;
    color: var(--text);
}

.logo p {
    margin: 4px 0 0 0;
    color: var(--text-light);
    font-size: 15px;
}

nav {
    display: flex;
    align-items: center;
    gap: 24px;
}

nav a {
    text-decoration: none;
    color: var(--text);
    font-weight: 600;
    transition: .25s;
}

nav a:hover {
    color: var(--primary);
}

.hero {
    background: var(--surface);
    padding: 45px 75px;
    margin-top: 25px;
    border-radius: var(--radius);
    box-shadow: 0 10px 30px var(--shadow);
}

.hero h2 {
    font-size: 58px;
    font-weight: 700;
    line-height: 1.05;
    letter-spacing: -1.5px;
    margin: 0 0 30px;
    color: var(--text);
}

.hero p {
    font-size: 21px;
    line-height: 1.8;
    color: var(--text-light);
    max-width: 720px;
    margin-bottom: 24px;
}

.button {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: var(--primary);
    color: white;
    padding: 16px 32px;
    border-radius: 999px;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: all .25s ease;
    box-shadow: 0 8px 20px rgba(37,99,235,.25);
}

.button:hover {
    background: var(--primary-dark);
    transform: translateY(-4px);
    box-shadow: 0 14px 30px rgba(37,99,235,.35);
}

.expertise {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 35px;
}

.expertise span {
    background: rgba(37,99,235,.08);
    color: var(--primary);
    padding: 10px 18px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 600;
    transition: all .25s ease;
}

.expertise span:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-2px);
}

.section-intro {
    max-width: 760px;
    margin: 65px 0 30px;
    text-align: left;
}
.eyebrow {
    color: var(--primary);
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    margin-bottom: 14px;
}
.section-intro h2 {
    font-size: 34px;
    line-height: 1.15;
    margin: 0;
    color: var(--text);
}
.section-intro p {
    color: var(--text-light);
    font-size: 18px;
    line-height: 1.7;
    margin-top: 16px;
}

.section-title h2 {
    font-size: 40px;
    margin: 0;
    color: var(--text);
}

.section-title p {
    margin-top: 12px;
    color: var(--text-light);
    font-size: 18px;
}

.cards {
    display: flex;
    gap: 30px;
    margin-top: 20px;
}

.card {
    background: var(--surface);
    padding: 35px;
    border-radius: var(--radius);
    flex: 1;
    box-shadow: 0 12px 30px var(--shadow);
    transition: all .3s ease;
    border: 1px solid transparent;
}

.card:hover {
    transform: translateY(-10px);
    border-color: rgba(37,99,235,.2);
    box-shadow: 0 18px 40px rgba(15,23,42,.15);
}

.card h3 {
    color: var(--text);
    margin: 0 0 18px;
    font-size: 28px;
}

.card p {
    line-height: 1.8;
    color: var(--text-light);
    font-size: 17px;
}

footer {
    text-align: center;
    margin-top: 50px;
    padding: 25px;
    background-color: #102a43;
    color: white;
}

/* ==========================
   Responsive Design
========================== */
@media (max-width: 768px) {
    .cards {
        flex-direction: column;
    }

    .hero {
        padding: 30px;
    }

    .hero h2 {
        font-size: 30px;
    }

    .site-header h1 {
        font-size: 34px;
    }

    nav {
    flex-direction: column;
    align-items: center;
    gap: 15px;

    }
    .hero {
    text-align: center;
    }

}

#themeButton {
    margin-left: 16px;
    background: var(--surface);
    color: var(--text);
    border: 1px solid #cbd5e1;
    padding: 10px 18px;
    border-radius: 999px;
    cursor: pointer;
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    transition: all .25s ease;
}

#themeButton:hover {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

body.dark-mode {
    --background: #0F172A;
    --surface: #1E293B;
    --text: #F8FAFC;
    --text-light: #CBD5E1;
}

.card-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, rgba(37,99,235,.18), rgba(6,182,212,.18));
    color: var(--primary);
    border-radius: 14px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 30px;
    margin-bottom: 20px;
}