:root {
    --blue: #062766;
    --light-blue: #1c73d8;
    --text: #10213d;
    --muted: #5f7191;
    --soft-blue: #eef6ff;
    --border: rgba(6, 39, 102, 0.10);
    --shadow: 0 18px 45px rgba(6, 39, 102, 0.12);
}

* {
    box-sizing: border-box;
}

html, body {
    min-height: 100vh;
    margin: 0;
    padding: 0;
}

body {
    display: flex;
    flex-direction: column;
    font-family: "Segoe UI", Arial, Helvetica, sans-serif;
    color: var(--blue);
    background: linear-gradient(135deg, #ffffff 0%, #f5f8ff 100%);
}

main {
    flex: 1;
    margin: 0;
    padding: 0;
}

/* HEADER */

header {
    position: absolute;
    top: 22px;
    left: 50%;
    transform: translateX(-50%);
    width: min(92%, 1680px);
    padding: 16px 28px;
    z-index: 100;
    background: rgba(255, 255, 255, 0.78);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    border: 1px solid var(--border);
    border-radius: 26px;
    box-shadow: 0 14px 40px rgba(6, 39, 102, 0.08);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 16px;
    text-decoration: none;
    color: var(--blue);
}

.logo-area img {
    width: 74px;
    height: 74px;
    object-fit: contain;
    filter: drop-shadow(0 8px 14px rgba(6, 39, 102, 0.12));
}

.logo-area h1 {
    margin: 0;
    font-size: 42px;
    line-height: 1;
    letter-spacing: -1px;
    font-weight: 800;
    color: var(--blue);
}

.logo-area p {
    margin: 6px 0 0;
    font-size: 17px;
    color: var(--muted);
    font-weight: 500;
}

nav {
    display: flex;
    align-items: center;
    gap: 14px;
}

nav a {
    position: relative;
    text-decoration: none;
    color: var(--blue);
    font-size: 18px;
    font-weight: 700;
    padding: 12px 18px;
    border-radius: 999px;
    transition: 0.25s ease;
}

nav a:hover {
    background: rgba(28, 115, 216, 0.10);
    color: var(--light-blue);
}

nav a:last-child {
    background: var(--blue);
    color: white;
    padding: 12px 26px;
    box-shadow: 0 10px 22px rgba(6, 39, 102, 0.18);
}

nav a:last-child:hover {
    background: var(--light-blue);
    color: white;
    transform: translateY(-2px);
}

/* HOME HERO */

.hero {
    padding-top: 140px;
    position: relative;
    min-height: calc(100vh - 70px);
    overflow: hidden;
    background: linear-gradient(135deg, #ffffff 0%, #eef6ff 100%);
}

.hero::before {
    content: "";
    position: absolute;
    width: 520px;
    height: 520px;
    right: -160px;
    top: 110px;
    background: radial-gradient(circle, rgba(28, 115, 216, 0.18), transparent 68%);
    pointer-events: none;
    z-index: 1;
}

.hero-image {
    width: 100%;    
    height: calc(100vh - 70px);
    object-fit: cover;
    object-position: center right;
    display: block;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(255,255,255,.96) 0%, rgba(255,255,255,.82) 33%, rgba(255,255,255,.34) 58%, rgba(255,255,255,0) 82%);
    z-index: 2;
}

/* HERO CONTENT */

.hero-content {
    position: absolute;
    left: clamp(35px, 7vw, 110px);
    top: 58%;
    transform: translateY(-50%);
    max-width: 520px;
    z-index: 3;
    padding: 26px 28px;
    border-radius: 28px;
    background: rgba(255,255,255,.60);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,.7);
}

    .hero-content h2 {
        margin: 0 0 28px;
        font-size: clamp(42px, 5vw, 58px);
        font-weight: 800;
        line-height: 1.05;
        letter-spacing: -1.5px;
        color: var(--blue);
    }

.blue-line {
    width: 70px;
    height: 5px;
    background: var(--light-blue);
    border-radius: 20px;
    margin: 20px 0 24px;
}

.hero-content p {
    margin: 0;
    font-size: 18px;
    line-height: 1.6;
    color: var(--text);
}

.hero-list {
    margin-top: 28px;
    padding: 22px 24px;
    background: rgba(255,255,255,.9);
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,.08);
    font-size: 20px;
    font-weight: 700;
    line-height: 1.55;
    color: var(--blue);
}

/* FOOTER */

/* FOOTER */

.footer {
    background: #062766;
    color: white;
    padding: 28px 40px;
    text-align: center;
}

.footer-brand h2 {
    margin: 0;
    font-size: 30px;
    font-weight: 800;
}

.footer-brand p {
    margin: 5px 0 20px;
    color: #cfe0ff;
    font-size: 15px;
}

.footer-contact {
    display: flex;
    justify-content: center;
    gap: 45px;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

    .footer-contact span {
        font-size: 16px;
        font-weight: 600;
    }

.footer-copy {
    margin: 0;
    color: #cfe0ff;
    font-size: 14px;
}

/* LOGIN PAGE */

.login-page {
    width: 92%;
    margin: 160px auto 70px;
    min-height: 520px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.login-card {
    width: 100%;
    max-width: 480px;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 46px;
    border-radius: 30px;
    box-shadow: var(--shadow);
    color: var(--blue);
    border: 1px solid var(--border);
}

.login-card h1 {
    margin: 0 0 12px;
    font-size: 44px;
    letter-spacing: -1px;
}

.login-card p {
    margin: 0 0 35px;
    color: var(--muted);
    font-size: 17px;
}

.form-group {
    margin-bottom: 22px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 700;
}

.form-group input {
    width: 100%;
    padding: 16px 17px;
    border: 1px solid #d8dce5;
    border-radius: 16px;
    font-size: 17px;
    outline: none;
    background: #fbfdff;
}

.form-group input:focus {
    border-color: var(--light-blue);
    box-shadow: 0 0 0 4px rgba(28, 115, 216, 0.12);
}

.login-card button {
    width: 100%;
    padding: 16px;
    background: var(--blue);
    color: white;
    border: none;
    border-radius: 16px;
    font-size: 18px;
    font-weight: 700;
    cursor: pointer;
    transition: 0.25s ease;
}

.login-card button:hover {
    background: var(--light-blue);
    transform: translateY(-2px);
}

.error-message {
    background-color: #ffe5e5;
    color: #b00020;
    border: 1px solid #ffb3b3;
    padding: 12px;
    border-radius: 12px;
    margin-bottom: 20px;
    text-align: center;
}

/* LESSONS PAGE */

.lessons-page {
    width: 92%;
    margin: 160px auto 70px;
    text-align: center;
}

.lessons-page h1 {
    font-size: clamp(40px, 5vw, 60px);
    color: var(--blue);
    margin-bottom: 10px;
    letter-spacing: -1px;
}

.lessons-page p {
    font-size: 19px;
    color: var(--muted);
    margin-bottom: 42px;
}

.lesson-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 28px;
}

.lesson-card {
    background: rgba(255,255,255,0.92);
    border-radius: 26px;
    padding: 38px 20px;
    text-decoration: none;
    color: var(--blue);
    box-shadow: 0 15px 40px rgba(6, 39, 102, 0.08);
    transition: 0.25s ease;
    border: 1px solid var(--border);
}

.lesson-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 24px 58px rgba(6, 39, 102, 0.16);
    border-color: rgba(28, 115, 216, 0.35);
}

.lesson-card span {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 74px;
    height: 74px;
    background: linear-gradient(135deg, var(--blue), var(--light-blue));
    color: white;
    border-radius: 22px;
    font-size: 32px;
    font-weight: bold;
    margin-bottom: 17px;
    box-shadow: 0 12px 25px rgba(6, 39, 102, 0.18);
}

.lesson-card p {
    margin: 0;
    font-weight: 700;
    font-size: 18px;
    color: var(--blue);
}

/* TABLET */

@media (max-width: 1100px) {
    header {
        position: static;
        transform: none;
        width: 100%;
        border-radius: 0;
        padding: 20px 35px;
        background: white;
    }

    .hero {
        display: flex;
        flex-direction: column;
        min-height: auto;
        overflow: visible;
    }

    .hero::before {
        display: none;
    }

    .hero-image {
        width: 100%;
        height: auto;
        display: block;
        object-fit: cover;
        object-position: center;
    }

    .hero-overlay {
        display: none;
    }

    .hero-content {
        position: static;
        transform: none;
        max-width: none;
        width: 100%;
        padding: 50px 60px 70px;
        background: white;
        border-radius: 0;
        border: none;
        box-sizing: border-box;
    }

    .hero-content h2 {
        font-size: 46px;
        line-height: 1.15;
    }

    .footer {
        min-height: 70px;
        height: auto;
        padding: 20px;
    }

    .lesson-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/*MOBILE*/

@media (max-width: 768px) {

    header {
        padding: 20px;
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }

    .logo-area {
        justify-content: center;
        gap: 10px;
    }

        .logo-area img {
            width: 56px;
            height: 56px;
        }

        .logo-area h1 {
            font-size: 31px;
        }

        .logo-area p {
            font-size: 14px;
        }

    nav {
        justify-content: center;
        flex-wrap: wrap;
        gap: 10px;
    }

        nav a {
            font-size: 16px;
            padding: 9px 13px;
        }

            nav a:last-child {
                padding: 9px 18px;
            }

    .hero-content {
        position: static;
        transform: none;
        max-width: 100%;
        margin: 25px;
        padding: 24px;
        border-radius: 22px;
    }

        .hero-content h2 {
            font-size: 42px;
            line-height: 1.08;
        }

        .hero-content p {
            font-size: 17px;
        }

    .hero-list {
        font-size: 18px;
        padding: 18px;
    }

    @media (max-width: 768px) {

        .footer {
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
            gap: 18px;
            padding: 28px 20px;
        }

        .footer-brand h2 {
            font-size: 28px;
            margin: 0;
        }

        .footer-brand p {
            font-size: 15px;
            margin: 4px 0 0;
            line-height: 1.4;
        }

        .footer-contact {
            display: flex;
            flex-direction: column;
            gap: 10px;
        }

            .footer-contact span {
                justify-content: center;
                font-size: 16px;
            }

        .footer-copy {
            font-size: 13px;
            line-height: 1.5;
            max-width: 280px;
            margin: 0;
        }
    }

    .lesson-grid {
        grid-template-columns: 1fr;
    }

    .lessons-page {
        margin: 40px auto;
    }

        .lessons-page h1 {
            font-size: 38px;
        }

    .login-page {
        margin: 40px auto;
        min-height: auto;
    }

    .login-card {
        width: calc(100% - 20px);
        padding: 30px;
    }
}


/* ABOUT PAGE */

.about-page {
    min-height: 100vh;
    padding: 170px 8% 70px;
    background: linear-gradient(135deg, #ffffff 0%, #eef6ff 100%);
}

.about-card {
    max-width: 1050px;
    margin: 0 auto;
    background: rgba(255,255,255,.88);
    border: 1px solid rgba(6,39,102,.10);
    border-radius: 32px;
    padding: 55px;
    box-shadow: 0 20px 50px rgba(6,39,102,.10);
}

.about-label {
    display: inline-block;
    background: #062766;
    color: white;
    padding: 10px 22px;
    border-radius: 30px;
    font-weight: 700;
    margin-bottom: 22px;
}

.about-card h1 {
    font-size: clamp(38px, 5vw, 60px);
    line-height: 1.05;
    color: #062766;
    margin: 0 0 30px;
    letter-spacing: -1.5px;
}

.about-card p {
    font-size: 20px;
    line-height: 1.75;
    color: #10213d;
    margin-bottom: 22px;
}

.about-highlight {
    background: #eef6ff;
    border-left: 6px solid #1c73d8;
    padding: 24px;
    border-radius: 18px;
    font-size: 21px;
    font-weight: 700;
    color: #062766;
    margin: 35px 0;
}

.about-card h2 {
    margin-top: 40px;
    font-size: 34px;
    color: #1c73d8;
}

@media (max-width: 768px) {
    .about-page {
        padding: 40px 20px;
    }

    .about-card {
        padding: 30px;
        border-radius: 24px;
    }

        .about-card p {
            font-size: 17px;
        }
}