/* ===== Base Reset & Typography ===== */

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family:
        ui-sans-serif,
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;
}

body {
    height: 100vh;
    overflow: hidden;
    background: #020617;
    color: #e5f6ff;
}

/* ===== Animated Background ===== */

.background {
    position: fixed;
    inset: 0;
    background: url("wave-bg.svg") center / cover no-repeat;
    will-change: transform;
    transform-origin: center;
    z-index: -1;
}

/* ===== Main Card ===== */

.card {
    max-width: 420px;
    margin: auto;
    margin-top: 12vh;
    padding: 2.5rem;
    border-radius: 22px;

    background: rgba(15, 23, 42, 0.55);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);

    box-shadow:
        0 30px 60px rgba(2, 6, 23, 0.6),
        inset 0 1px 0 rgba(255, 255, 255, 0.05);

    text-align: center;
}

/* ===== Headings & Text ===== */

h1 {
    font-size: 2.4rem;
    margin-bottom: 1rem;
    color: #e5f6ff;
    letter-spacing: -0.02em;
}

h1 span {
    color: #67e8f9;
}

.subtitle {
    color: #c7d2fe;
    margin-bottom: 2rem;
    line-height: 1.55;
}

/* ===== Referral Code Box ===== */

.referral-box {
    margin-bottom: 1.8rem;
}

.referral-box span {
    display: block;
    font-size: 0.85rem;
    color: #a5b4fc;
    letter-spacing: 0.06em;
    margin-bottom: 0.4rem;
}

.code {
    font-size: 1.9rem;
    font-weight: 600;
    letter-spacing: 0.18em;
    padding: 0.7rem 1.2rem;
    border-radius: 14px;

    color: #ecfeff;
    background: linear-gradient(
        135deg,
        rgba(34, 211, 238, 0.25),
        rgba(45, 212, 191, 0.25)
    );

    border: 1px solid rgba(165, 243, 252, 0.35);
    cursor: pointer;
    user-select: none;

    transition:
        transform 0.15s ease,
        box-shadow 0.15s ease,
        background 0.15s ease;
}

.code:hover {
    transform: translateY(-1px);
    box-shadow: 0 8px 20px rgba(103, 232, 249, 0.35);
}

.code:active {
    transform: scale(0.98);
}

/* Copied state */
.code.copied {
    background: linear-gradient(
        135deg,
        rgba(56, 189, 248, 0.45),
        rgba(34, 211, 238, 0.45)
    );
    box-shadow: 0 0 0 2px rgba(56, 189, 248, 0.4);
}

/* ===== CTA Button ===== */

.cta {
    display: inline-block;
    margin-top: 1.2rem;
    padding: 0.95rem 1.8rem;

    background: linear-gradient(135deg, #38bdf8, #22d3ee);
    color: #022c22;
    font-weight: 700;
    font-size: 0.95rem;

    border-radius: 999px;
    text-decoration: none;

    transition:
        transform 0.15s ease,
        box-shadow 0.15s ease;
}

.cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(56, 189, 248, 0.45);
}

.cta:active {
    transform: scale(0.97);
}

/* ===== Small Hint Text ===== */

.hint {
    margin-top: 1.4rem;
    font-size: 0.85rem;
    color: #94a3b8;
}

/* ===== Responsive ===== */

@media (max-width: 480px) {
    .card {
        margin-top: 8vh;
        padding: 2rem 1.6rem;
    }

    h1 {
        font-size: 2rem;
    }

    .code {
        font-size: 1.6rem;
    }
}