:root {
    --red: #be1e2d;
    --black: #1a1a1a;
    --white: #ffffff;
    --green: #2ecc71;
}

* {
    box-sizing: border-box;
}

html,
body {
    overflow-x: hidden;
    max-width: 100%;
}

body {
    font-family: 'Arial Black', sans-serif;
    background-color: var(--red);
    color: var(--black);
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 2vh;
    text-transform: uppercase;
}

.container {
    background: var(--white);
    padding: 4vh 4vw;
    border: 8px solid var(--black);
    box-shadow: 1.5vh 1.5vh 0px var(--black);
    width: 100%;
    max-width: 450px;
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 2vh;
}

h1 {
    color: var(--black);
    margin: 0;
    font-size: clamp(2.5rem, 5vh, 4rem);
    font-weight: 900;
    letter-spacing: 2px;
}

.info {
    background: #eee;
    border: 4px solid var(--black);
    padding: 1.5vh;
    font-size: clamp(0.9rem, 2vh, 1.3rem);
    font-weight: 900;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 1vh;
    line-height: 1.3;
}

.info span {
    color: var(--red);
}

.amount-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1vh;
}

.amount-label {
    font-size: clamp(1.2rem, 2.5vh, 1.5rem);
    font-weight: 900;
}

.amount-input-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    border: 4px solid var(--black);
    background: var(--white);
    width: 100%;
}

.btn-adj {
    width: 7vh;
    height: 7vh;
    background: var(--black);
    color: var(--white);
    border: none;
    font-size: clamp(1.5rem, 3vh, 2rem);
    font-weight: 900;
    cursor: pointer;
    font-family: 'Arial Black', sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-adj:active {
    background: var(--red);
}

input[type="number"] {
    flex: 1;
    width: 100%;
    padding: 0;
    height: 7vh;
    font-size: clamp(1.5rem, 3.5vh, 2.5rem);
    font-weight: 900;
    text-align: center;
    border: none;
    font-family: 'Arial Black', sans-serif;
    color: var(--red);
    outline: none;
    appearance: textfield;
    -moz-appearance: textfield;
    background: transparent;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.currency {
    padding-right: 1.5vh;
    font-size: clamp(1rem, 2vh, 1.5rem);
    font-weight: 900;
    color: var(--black);
}

#liqpay_checkout {
    width: 100%;
    min-height: 400px;
    display: flex;
    flex-direction: column;
}

#liqpay_checkout iframe {
    width: 100% !important;
    min-height: 400px !important;
    border: none !important;
    flex-grow: 1;
}

.modal-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal-overlay.active {
    display: flex;
}

.modal-box {
    background: var(--white);
    border: 8px solid var(--black);
    padding: 4vh 4vw;
    max-width: 90vw;
    width: 400px;
    text-align: center;
    box-shadow: 1.5vh 1.5vh 0px var(--black);
}

.modal-text {
    font-size: clamp(1.2rem, 2.5vh, 2rem);
    font-weight: 900;
    color: var(--black);
    margin-bottom: 3vh;
}

.modal-btn {
    width: 100%;
    padding: 1.5vh;
    font-size: clamp(1rem, 2vh, 1.5rem);
    font-weight: 900;
    border: 4px solid var(--black);
    cursor: pointer;
    font-family: 'Arial Black', sans-serif;
    background: var(--green);
    color: var(--black);
    box-shadow: 4px 4px 0px var(--black);
    transition: transform 0.1s, box-shadow 0.1s, background-color 0.2s;
}
.modal-btn:hover {
    background: #27ae60;
}
.modal-btn:active {
    transform: translate(4px, 4px);
    box-shadow: 0px 0px 0px var(--black);
}

.quick-btns {
    display: flex;
    gap: 2vw;
    width: 100%;
    justify-content: space-between;
    margin-top: 1vh;
}

.btn-quick {
    flex: 1;
    background: #eee;
    border: 4px solid var(--black);
    color: var(--black);
    font-size: clamp(1.2rem, 2.5vh, 1.5rem);
    font-weight: 900;
    padding: 1.5vh 0;
    cursor: pointer;
    font-family: 'Arial Black', sans-serif;
    box-shadow: 4px 4px 0px var(--black);
    transition: transform 0.1s, box-shadow 0.1s, background-color 0.2s;
}
.btn-quick:hover {
    background: #dddddd;
}

.btn-quick:active {
    transform: translate(4px, 4px);
    box-shadow: 0px 0px 0px var(--black);
}