/* =========================================================
   RESET
========================================================= */

* {
    box-sizing: border-box;
}


/* =========================================================
   PAGE
========================================================= */

.grade-four-body {
    margin: 0;
    min-height: 100vh;

    position: relative;
    overflow-x: hidden;

    background:
        radial-gradient(
            circle at 8% 12%,
            rgba(151, 105, 220, 0.22),
            transparent 27%
        ),
        radial-gradient(
            circle at 92% 8%,
            rgba(181, 139, 235, 0.20),
            transparent 28%
        ),
        radial-gradient(
            circle at 82% 72%,
            rgba(205, 177, 241, 0.18),
            transparent 30%
        ),
        radial-gradient(
            circle at 12% 82%,
            rgba(126, 78, 190, 0.12),
            transparent 26%
        ),
        linear-gradient(
            180deg,
            #f8f4fd 0%,
            #fdfbff 45%,
            #f5effc 100%
        );

    color: #3f3748;
}


/* =========================================================
   DECORATIVE BACKGROUND
========================================================= */

.grade-four-body::before {
    content: "";

    position: fixed;

    width: 460px;
    height: 460px;

    left: -180px;
    top: 180px;

    border-radius: 50%;

    background:
        linear-gradient(
            145deg,
            rgba(181, 139, 235, 0.18),
            rgba(226, 208, 247, 0.08)
        );

    filter: blur(2px);

    pointer-events: none;
    z-index: 0;
}


.grade-four-body::after {
    content: "";

    position: fixed;

    width: 520px;
    height: 520px;

    right: -230px;
    bottom: 40px;

    border-radius: 50%;

    background:
        linear-gradient(
            145deg,
            rgba(151, 105, 220, 0.15),
            rgba(205, 177, 241, 0.07)
        );

    pointer-events: none;
    z-index: 0;
}


.grade-four-header,
.grade-four-main {
    position: relative;
    z-index: 2;
}


/* =========================================================
   HEADER
========================================================= */

.grade-four-header {
    padding: 22px 24px 0;
}


.grade-four-nav {
    width: 100%;
    max-width: 1180px;

    margin: 0 auto;
    padding: 14px 18px 14px 26px;

    display: flex;
    align-items: center;
    justify-content: space-between;

    background: rgba(255, 255, 255, 0.88);

    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);

    border: 1px solid rgba(126, 78, 190, 0.16);
    border-radius: 24px;

    box-shadow:
        0 12px 32px
        rgba(93, 57, 139, 0.09);
}


.grade-four-body .logo {
    padding: 12px 20px;

    background:
        linear-gradient(
            135deg,
            #8554c7,
            #ad7ce3
        );

    border-radius: 16px;

    color: white;

    font-size: 24px;
    font-weight: 800;
    letter-spacing: 2px;

    text-decoration: none;

    box-shadow:
        0 8px 20px
        rgba(126, 78, 190, 0.20);
}


.grade-four-body .nav-links {
    margin: 0;
    padding: 0;

    display: flex;
    align-items: center;
    gap: 8px;

    list-style: none;
}


.grade-four-body .nav-links a {
    display: block;

    padding: 11px 18px;

    border-radius: 14px;

    color: #5b5066;

    font-weight: 700;
    text-decoration: none;

    transition:
        transform 0.25s ease,
        background 0.25s ease,
        color 0.25s ease;
}


.grade-four-body .nav-links a:hover {
    background: #f0e6fb;
    color: #7040ad;

    transform: translateY(-2px);
}


.grade-four-body .nav-links a.active {
    background:
        linear-gradient(
            135deg,
            #8554c7,
            #a873df
        );

    color: white;
}


/* =========================================================
   MAIN
========================================================= */

.grade-four-main {
    width: min(1120px, 90%);

    margin: 0 auto;
    padding: 65px 0 100px;
}


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

.grade-four-hero {
    max-width: 760px;

    margin: 55px auto 65px;

    position: relative;

    text-align: center;
}


.grade-four-hero::before {
    content: "";

    position: absolute;

    width: 330px;
    height: 170px;

    left: 50%;
    top: 10px;

    transform: translateX(-50%);

    background:
        radial-gradient(
            ellipse,
            rgba(151, 105, 220, 0.15),
            transparent 70%
        );

    filter: blur(8px);

    pointer-events: none;
    z-index: -1;
}


.back-link {
    display: inline-block;

    margin-bottom: 28px;

    color: #7040ad;

    font-weight: 700;
    text-decoration: none;

    transition:
        transform 0.25s ease,
        color 0.25s ease;
}


.back-link:hover {
    color: #573087;

    transform: translateX(-4px);
}


.hero-icon {
    width: 92px;
    height: 92px;

    margin: 0 auto 20px;

    display: flex;
    align-items: center;
    justify-content: center;

    background:
        linear-gradient(
            145deg,
            #eee0fa,
            #d9bff1
        );

    border: 1px solid rgba(133, 84, 199, 0.12);
    border-radius: 28px;

    font-size: 48px;

    box-shadow:
        0 12px 30px
        rgba(111, 67, 168, 0.14);
}


.grade-label,
.section-label {
    margin: 0 0 10px;

    color: #8554c7;

    font-size: 13px;
    font-weight: 800;
    letter-spacing: 2px;
}


.grade-four-hero h1 {
    margin: 0 0 18px;

    color: #573087;

    font-size: clamp(40px, 6vw, 66px);
    line-height: 1.08;
}


.hero-description {
    max-width: 620px;

    margin: 0 auto;

    color: #746a7d;

    font-size: 18px;
    line-height: 1.7;
}


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

.units-section {
    padding: 36px;

    position: relative;
    overflow: hidden;

    background: rgba(255, 255, 255, 0.72);

    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);

    border: 1px solid rgba(126, 78, 190, 0.14);
    border-radius: 34px;

    box-shadow:
        0 18px 45px
        rgba(93, 57, 139, 0.09);
}


.units-section::before {
    content: "GRADE 4";

    position: absolute;

    right: -20px;
    top: 50px;

    color: rgba(126, 78, 190, 0.045);

    font-size: 120px;
    font-weight: 900;
    letter-spacing: 7px;

    transform: rotate(-7deg);

    pointer-events: none;
}


.units-section::after {
    content: "";

    position: absolute;

    width: 240px;
    height: 240px;

    right: -110px;
    bottom: -110px;

    border-radius: 50%;

    background:
        radial-gradient(
            circle,
            rgba(181, 139, 235, 0.16),
            transparent 70%
        );

    pointer-events: none;
}


.section-heading {
    margin-bottom: 30px;

    position: relative;
    z-index: 2;

    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 20px;
}


.section-heading h2 {
    margin: 0;

    color: #573087;

    font-size: 32px;
}


.unit-count {
    padding: 10px 15px;

    background: #eadcf8;

    border: 1px solid rgba(133, 84, 199, 0.10);
    border-radius: 999px;

    color: #7040ad;

    font-size: 14px;
    font-weight: 800;
}


.units-grid {
    position: relative;
    z-index: 2;

    display: grid;

    grid-template-columns:
        repeat(2, minmax(0, 1fr));

    gap: 22px;
}


/* =========================================================
   ALL LESSON CARDS
========================================================= */

.unit-card {
    min-height: 300px;
    padding: 26px;

    display: flex;
    flex-direction: column;

    position: relative;
    overflow: hidden;

    border: 1px solid rgba(126, 78, 190, 0.18);
    border-radius: 28px;

    background: #eadcf8;

    color: #3f3748;

    text-decoration: none;

    box-shadow:
        0 10px 28px
        rgba(93, 57, 139, 0.08);

    transition:
        transform 0.3s ease,
        box-shadow 0.3s ease,
        border-color 0.3s ease;
}


.unit-card::before {
    content: "";

    position: absolute;

    width: 230px;
    height: 230px;

    right: -110px;
    top: -115px;

    border-radius: 50%;

    background: rgba(255, 255, 255, 0.18);

    pointer-events: none;
}


.unit-card::after {
    content: "";

    position: absolute;

    width: 70px;
    height: 70px;

    right: 28px;
    bottom: 55px;

    border: 1px solid rgba(133, 84, 199, 0.10);
    border-radius: 50%;

    background: rgba(255, 255, 255, 0.10);

    pointer-events: none;
}


a.unit-card:hover {
    transform: translateY(-7px);

    border-color: rgba(126, 78, 190, 0.30);

    box-shadow:
        0 20px 42px
        rgba(93, 57, 139, 0.15);
}


/* =========================================================
   ALL 12 LESSONS — SAME PURPLE COLOR
========================================================= */

.unit-card,
.unit-one,
.unit-two,
.unit-three,
.unit-four,
.unit-five,
.unit-six,
.unit-seven,
.unit-eight,
.unit-nine,
.unit-ten,
.unit-eleven,
.unit-twelve {
    background: #eadcf8 !important;

    border:
        1px solid
        rgba(126, 78, 190, 0.18) !important;

    box-shadow:
        0 10px 28px
        rgba(93, 57, 139, 0.08) !important;
}


/* =========================================================
   SAME DECORATION FOR ALL 12 LESSONS
========================================================= */

.unit-card::before,
.unit-one::before,
.unit-two::before,
.unit-three::before,
.unit-four::before,
.unit-five::before,
.unit-six::before,
.unit-seven::before,
.unit-eight::before,
.unit-nine::before,
.unit-ten::before,
.unit-eleven::before,
.unit-twelve::before {
    content: "";

    position: absolute;

    width: 230px;
    height: 230px;

    right: -110px;
    top: -115px;

    border-radius: 50%;

    background:
        rgba(255, 255, 255, 0.18) !important;

    pointer-events: none;
}


/* =========================================================
   SAME ICON BACKGROUND FOR ALL 12 LESSONS
========================================================= */

.unit-card .unit-icon,
.unit-one .unit-icon,
.unit-two .unit-icon,
.unit-three .unit-icon,
.unit-four .unit-icon,
.unit-five .unit-icon,
.unit-six .unit-icon,
.unit-seven .unit-icon,
.unit-eight .unit-icon,
.unit-nine .unit-icon,
.unit-ten .unit-icon,
.unit-eleven .unit-icon,
.unit-twelve .unit-icon {
    background:
        rgba(255, 255, 255, 0.72) !important;

    border:
        1px solid
        rgba(126, 78, 190, 0.12) !important;
}


/* =========================================================
   HOVER — ALL 12 LESSONS
========================================================= */

a.unit-card:hover,
a.unit-one:hover,
a.unit-two:hover,
a.unit-three:hover,
a.unit-four:hover,
a.unit-five:hover,
a.unit-six:hover,
a.unit-seven:hover,
a.unit-eight:hover,
a.unit-nine:hover,
a.unit-ten:hover,
a.unit-eleven:hover,
a.unit-twelve:hover {
    background:
        #eadcf8 !important;

    transform:
        translateY(-7px);

    box-shadow:
        0 20px 42px
        rgba(93, 57, 139, 0.15) !important;
}


/* =========================================================
   CARD CONTENT
========================================================= */

.unit-top {
    position: relative;
    z-index: 2;

    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}


.unit-number {
    color: #8554c7;

    font-size: 12px;
    font-weight: 900;
    letter-spacing: 1.5px;
}


.unit-status {
    padding: 7px 11px;

    background: rgba(255, 255, 255, 0.70);

    border: 1px solid rgba(133, 84, 199, 0.08);
    border-radius: 999px;

    color: #83778c;

    font-size: 12px;
    font-weight: 800;
}


.unit-status.available {
    background:
        linear-gradient(
            135deg,
            #8554c7,
            #a873df
        );

    color: white;

    box-shadow:
        0 6px 14px
        rgba(126, 78, 190, 0.15);
}


/* =========================================================
   ICONS — ALL 12 LESSONS
========================================================= */

.unit-icon,
.unit-one .unit-icon,
.unit-two .unit-icon,
.unit-three .unit-icon,
.unit-four .unit-icon,
.unit-five .unit-icon,
.unit-six .unit-icon,
.unit-seven .unit-icon,
.unit-eight .unit-icon,
.unit-nine .unit-icon,
.unit-ten .unit-icon,
.unit-eleven .unit-icon,
.unit-twelve .unit-icon {
    width: 68px;
    height: 68px;

    margin: 30px 0 20px;

    position: relative;
    z-index: 2;

    display: flex;
    align-items: center;
    justify-content: center;

    background:
        linear-gradient(
            145deg,
            rgba(255, 255, 255, 0.92),
            #e7d5f7
        );

    border: 1px solid rgba(133, 84, 199, 0.12);
    border-radius: 22px;

    color: #8554c7;

    font-size: 36px;

    box-shadow:
        0 9px 20px
        rgba(93, 57, 139, 0.09);

    transition:
        transform 0.3s ease,
        box-shadow 0.3s ease;
}


.unit-card:hover .unit-icon {
    transform:
        translateY(-3px)
        rotate(-3deg)
        scale(1.04);

    box-shadow:
        0 13px 25px
        rgba(93, 57, 139, 0.13);
}


/* =========================================================
   TITLES
========================================================= */

.unit-card h3 {
    margin: 0 0 11px;

    position: relative;
    z-index: 2;

    color: #573087;

    font-size: 24px;
}


.unit-card p {
    margin: 0 0 24px;

    position: relative;
    z-index: 2;

    color: #70647a;

    line-height: 1.6;
}


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

.unit-footer {
    margin-top: auto;

    position: relative;
    z-index: 2;

    display: flex;
    align-items: center;
    justify-content: space-between;

    color: #7040ad;

    font-size: 14px;
    font-weight: 800;
}


/* =========================================================
   START BUTTON
========================================================= */

.start-btn {
    padding: 12px 20px;

    background:
        rgba(255, 255, 255, 0.90);

    border: 1px solid rgba(133, 84, 199, 0.10);

    color: #7040ad;

    border-radius: 999px;

    font-weight: 700;

    box-shadow:
        0 6px 15px
        rgba(93, 57, 139, 0.06);

    transition:
        transform 0.25s ease,
        background 0.25s ease,
        box-shadow 0.25s ease;
}


.unit-card:hover .start-btn {
    transform: translateX(6px);

    background: white;

    box-shadow:
        0 8px 18px
        rgba(93, 57, 139, 0.10);
}


/* =========================================================
   EXTRA BACKGROUND DETAILS
========================================================= */

.grade-four-main::before {
    content: "";

    position: absolute;

    width: 16px;
    height: 16px;

    left: -25px;
    top: 420px;

    border-radius: 50%;

    background:
        rgba(133, 84, 199, 0.20);

    box-shadow:
        55px -90px 0 7px rgba(181, 139, 235, 0.08),
        1060px 160px 0 11px rgba(133, 84, 199, 0.07),
        1010px 620px 0 5px rgba(181, 139, 235, 0.12),
        20px 950px 0 9px rgba(133, 84, 199, 0.07);

    pointer-events: none;
}


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

@media (max-width: 750px) {

    .grade-four-header {
        padding: 12px;
    }


    .grade-four-nav {
        width: 100%;
        max-width: none;

        padding: 16px;

        flex-direction: column;
        gap: 14px;

        border-radius: 20px;
    }


    .grade-four-body .logo {
        padding: 10px 18px;

        font-size: 22px;
        letter-spacing: normal;
    }


    .grade-four-body .nav-links {
        width: 100%;

        justify-content: center;
        flex-wrap: wrap;
    }


    .grade-four-body .nav-links a {
        padding: 8px 14px;

        font-size: 14px;
    }


    .grade-four-main {
        width: calc(100% - 24px);

        padding: 48px 0 70px;
    }


    .grade-four-hero {
        margin-top: 100px;
    }


    .units-section {
        padding: 24px 17px;

        border-radius: 26px;
    }


    .units-section::before {
        right: -35px;
        top: 80px;

        font-size: 70px;
    }


    .section-heading {
        align-items: flex-start;
        flex-direction: column;
    }


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


    .unit-card {
        min-height: 280px;
        padding: 23px;
    }


    .unit-one {
        grid-column: span 1;
    }


    .grade-four-main::before {
        display: none;
    }

}


/* =========================================================
   SMALL MOBILE
========================================================= */

@media (max-width: 480px) {

    .grade-four-main {
        width: calc(100% - 18px);
    }


    .grade-four-hero h1 {
        font-size: 42px;
    }


    .hero-description {
        font-size: 16px;
    }


    .units-section {
        padding: 20px 14px;
    }


    .unit-card {
        min-height: 265px;
        padding: 20px;
    }


    .unit-card h3 {
        font-size: 21px;
    }


    .unit-icon {
        width: 62px;
        height: 62px;

        margin: 26px 0 18px;

        font-size: 32px;
    }


    .start-btn {
        padding: 10px 16px;
    }

}