```css
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}


:root {

    --background: #08090d;

    --surface: #11131a;

    --surface-light: #181b24;

    --border: rgba(255,255,255,.08);

    --text: #f7f7f8;

    --muted: #9297a5;

    --accent: #8b7cff;

    --accent-2: #6c5ce7;
}


html {
    min-height: 100%;
}


body {

    font-family:
        Inter,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;

    background:
        var(--background);

    color:
        var(--text);

    min-height:
        100vh;

    -webkit-font-smoothing:
        antialiased;
}


button {

    font: inherit;

    border: 0;

    cursor: pointer;

    -webkit-tap-highlight-color:
        transparent;
}


/* =========================================
   APP
========================================= */

.app {

    width:
        100%;

    max-width:
        520px;

    min-height:
        100vh;

    margin:
        auto;

    padding-bottom:
        105px;
}


/* =========================================
   TOP BAR
========================================= */

.topbar {

    height:
        70px;

    padding:
        0 20px;

    display:
        flex;

    align-items:
        center;

    justify-content:
        space-between;
}


.brand {

    display:
        flex;

    align-items:
        center;
}


.brand-mark {

    font-size:
        24px;

    margin-right:
        8px;

    color:
        #b9b0ff;
}


.brand-name {

    font-size:
        18px;

    font-weight:
        750;

    letter-spacing:
        -.3px;
}


.profile-button {

    width:
        38px;

    height:
        38px;

    border-radius:
        50%;

    background:
        var(--surface-light);

    color:
        white;

    border:
        1px solid var(--border);
}


/* =========================================
   WELCOME
========================================= */

.welcome {

    padding:
        30px 20px 24px;
}


.eyebrow {

    color:
        var(--muted);

    font-size:
        10px;

    font-weight:
        750;

    letter-spacing:
        1.5px;

    text-transform:
        uppercase;

    margin-bottom:
        8px;
}


.welcome h1 {

    font-size:
        31px;

    letter-spacing:
        -1px;

    margin-bottom:
        10px;
}


.subtitle {

    color:
        var(--muted);

    line-height:
        1.55;

    font-size:
        14px;

    max-width:
        390px;
}


/* =========================================
   BALANCE CARD
========================================= */

.balance-card {

    margin:
        0 20px;

    padding:
        22px;

    border-radius:
        24px;

    background:
        linear-gradient(
            135deg,
            #242039,
            #11131a
        );

    border:
        1px solid var(--border);

    box-shadow:
        0 20px 60px
        rgba(0,0,0,.18);
}


.balance-header,
.balance-footer {

    display:
        flex;

    justify-content:
        space-between;

    align-items:
        center;

    color:
        var(--muted);

    font-size:
        12px;
}


.status-dot {

    width:
        7px;

    height:
        7px;

    border-radius:
        50%;

    background:
        #55d88a;

    box-shadow:
        0 0 10px
        rgba(85,216,138,.5);
}


.balance {

    display:
        flex;

    align-items:
        baseline;

    gap:
        7px;

    margin:
        18px 0;
}


.balance span {

    font-size:
        46px;

    font-weight:
        800;

    letter-spacing:
        -2px;
}


.balance small {

    color:
        var(--muted);

    font-weight:
        700;
}


/* =========================================
   SECTIONS
========================================= */

.featured,
.activity {

    padding:
        30px 20px 0;
}


.section-heading {

    display:
        flex;

    align-items:
        end;

    justify-content:
        space-between;

    margin-bottom:
        14px;
}


.section-heading h2 {

    font-size:
        21px;

    letter-spacing:
        -.5px;
}


/* =========================================
   VIDEO CARD
========================================= */

.video-card {

    display:
        flex;

    align-items:
        center;

    gap:
        13px;

    padding:
        15px;

    border:
        1px solid var(--border);

    background:
        var(--surface);

    border-radius:
        20px;

    transition:
        border-color .2s,
        transform .2s;
}


.video-card:hover {

    border-color:
        rgba(139,124,255,.25);

}


.video-icon {

    width:
        48px;

    height:
        48px;

    flex:
        0 0 48px;

    display:
        grid;

    place-items:
        center;

    border-radius:
        15px;

    background:
        #211d38;

    color:
        #b9b0ff;

    font-size:
        16px;
}


.video-info {

    flex:
        1;

    min-width:
        0;
}


.video-info h3 {

    font-size:
        14px;

    margin-bottom:
        5px;
}


.video-info p {

    color:
        var(--muted);

    font-size:
        11px;

    line-height:
        1.4;
}


/* =========================================
   WATCH BUTTON
========================================= */

.watch-button {

    min-width:
        72px;

    height:
        40px;

    padding:
        0 15px;

    border-radius:
        12px;

    background:
        linear-gradient(
            135deg,
            var(--accent),
            var(--accent-2)
        );

    color:
        white;

    font-size:
        12px;

    font-weight:
        750;

    box-shadow:
        0 8px 20px
        rgba(108,92,231,.22);

    transition:
        transform .15s,
        opacity .15s;
}


.watch-button:active {

    transform:
        scale(.96);
}


.watch-button:disabled {

    opacity:
        .5;

    cursor:
        not-allowed;
}


/* =========================================
   ACTIVITY
========================================= */

.text-button {

    background:
        transparent;

    color:
        var(--accent);

    font-size:
        12px;
}


.activity-list {

    display:
        flex;

    flex-direction:
        column;

    gap:
        8px;
}


.empty-state {

    padding:
        25px;

    text-align:
        center;

    border-radius:
        17px;

    background:
        var(--surface);

    border:
        1px solid var(--border);

    color:
        var(--muted);

    font-size:
        12px;
}


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

.bottom-nav {

    position:
        fixed;

    left:
        50%;

    bottom:
        14px;

    transform:
        translateX(-50%);

    width:
        min(480px, calc(100% - 28px));

    display:
        grid;

    grid-template-columns:
        repeat(4, 1fr);

    padding:
        8px;

    background:
        rgba(17,19,26,.94);

    backdrop-filter:
        blur(20px);

    -webkit-backdrop-filter:
        blur(20px);

    border:
        1px solid var(--border);

    border-radius:
        22px;

    z-index:
        100;
}


.nav-item {

    padding:
        8px 4px;

    background:
        transparent;

    color:
        var(--muted);

    display:
        flex;

    flex-direction:
        column;

    align-items:
        center;

    gap:
        4px;
}


.nav-item span {

    font-size:
        16px;
}


.nav-item small {

    font-size:
        9px;
}


.nav-item.active {

    color:
        white;
}


/* =========================================
   CUSTOM POPUP
========================================= */

.custom-popup {

    position:
        fixed;

    inset:
        0;

    z-index:
        999999;

    display:
        flex;

    align-items:
        center;

    justify-content:
        center;

    padding:
        20px;
}


.custom-popup.hidden {

    display:
        none;
}


/* BACKDROP */

.popup-backdrop {

    position:
        absolute;

    inset:
        0;

    background:
        rgba(0,0,0,.78);

    backdrop-filter:
        blur(10px);

    -webkit-backdrop-filter:
        blur(10px);
}


/* POPUP CARD */

.popup-card {

    position:
        relative;

    z-index:
        2;

    width:
        100%;

    max-width:
        350px;

    padding:
        28px 22px 22px;

    text-align:
        center;

    border:
        1px solid
        rgba(255,255,255,.1);

    border-radius:
        25px;

    background:
        linear-gradient(
            145deg,
            #282340,
            #11131a
        );

    box-shadow:
        0 30px 100px
        rgba(0,0,0,.7);

    animation:
        popupAppear .2s ease-out;
}


@keyframes popupAppear {

    from {

        opacity:
            0;

        transform:
            translateY(15px)
            scale(.94);
    }

    to {

        opacity:
            1;

        transform:
            translateY(0)
            scale(1);
    }
}


/* POPUP ICON */

.popup-icon {

    width:
        58px;

    height:
        58px;

    margin:
        0 auto 17px;

    display:
        grid;

    place-items:
        center;

    border-radius:
        18px;

    background:
        rgba(139,124,255,.14);

    border:
        1px solid
        rgba(139,124,255,.2);

    color:
        #b9b0ff;

    font-size:
        25px;

    font-weight:
        800;
}


/* POPUP TITLE */

.popup-card h2 {

    color:
        white;

    font-size:
        20px;

    margin-bottom:
        9px;
}


/* POPUP MESSAGE */

.popup-card p {

    color:
        var(--muted);

    font-size:
        13px;

    line-height:
        1.55;

    margin-bottom:
        22px;
}


/* POPUP BUTTON */

.popup-button {

    width:
        100%;

    height:
        45px;

    border-radius:
        13px;

    background:
        linear-gradient(
            135deg,
            var(--accent),
            var(--accent-2)
        );

    color:
        white;

    font-size:
        13px;

    font-weight:
        800;

    cursor:
        pointer;
}


.popup-button:active {

    transform:
        scale(.98);
}


/* =========================================
   SMALL PHONES
========================================= */

@media (max-width: 380px) {

    .video-card {

        gap:
            9px;
    }


    .video-icon {

        width:
            42px;

        height:
            42px;

        flex-basis:
            42px;
    }


    .watch-button {

        min-width:
            64px;

        padding:
            0 10px;
    }

}
```