/* Minimalist Black & White Theme */
:root {
    --bg: #ffffff;
    --card-bg: #ffffff;
    --text: #111111;
    --muted: #666666;
    --border: #e6e6e6;
    --button-bg: #111111;
    --button-text: #ffffff;
}

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

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    width: 100%;
    max-width: 480px;
    padding: 32px;
    box-shadow: none;
}

h2 {
    text-align: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text);
}

.row {
    margin-bottom: 16px;
}

label {
    display: block;
    font-size: 0.75rem;
    color: var(--muted);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

input,
textarea {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: #fff;
    color: var(--text);
    font-size: 1rem;
}

input::placeholder {
    color: #999;
}

button {
    width: 100%;
    padding: 12px 14px;
    margin-top: 8px;
    background: var(--button-bg);
    color: var(--button-text);
    border: none;
    border-radius: 8px;
    font-weight: 700;
    cursor: pointer;
}

#res-box {
    margin-top: 18px;
    padding: 16px;
    min-height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #fafafa;
    border: 1px dashed var(--border);
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 1.1rem;
    color: var(--text);
    word-break: break-all;
    text-align: center;
    cursor: pointer;
}

.copied-toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: #111;
    color: #fff;
    padding: 8px 14px;
    border-radius: 6px;
    font-size: 0.9rem;
    z-index: 1000;
}

.hint {
    text-align: center;
    margin-top: 18px;
    font-size: 0.8rem;
    color: var(--muted);
}

@media (max-width: 480px) {
    .card {
        padding: 20px;
        border-radius: 10px;
    }

    h2 {
        font-size: 1.25rem;
    }

    #res-box {
        font-size: 1rem;
        padding: 12px;
    }
}

input {
    padding: 12px 14px;
}

#res-box {
    font-size: 1.2rem;
    padding: 16px;
}

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

input[type="number"] {
    -moz-appearance: textfield;
    appearance: textfield;
}