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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #0a0a0a;
    color: #e0e0e0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    background: #1a1a1a;
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    width: 100%;
    max-width: 400px;
    text-align: center;
}

h1 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 32px;
    color: #ffffff;
}

label {
    display: block;
    text-align: left;
    font-size: 14px;
    color: #888;
    margin-bottom: 8px;
}

input {
    width: 100%;
    padding: 14px 16px;
    font-size: 18px;
    font-family: 'SF Mono', 'Fira Code', monospace;
    background: #0d0d0d;
    border: 2px solid #333;
    border-radius: 8px;
    color: #fff;
    text-align: center;
    letter-spacing: 2px;
    transition: border-color 0.2s;
}

input:focus {
    outline: none;
    border-color: #4ade80;
}

input::placeholder {
    color: #444;
    letter-spacing: 1px;
}

button {
    width: 100%;
    padding: 14px;
    margin-top: 16px;
    font-size: 16px;
    font-weight: 600;
    background: #4ade80;
    color: #000;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

button:hover {
    background: #22c55e;
}

button:active {
    transform: scale(0.98);
}

#clear-btn {
    background: #333;
    color: #888;
}

#clear-btn:hover {
    background: #444;
    color: #fff;
}

#code-section {
    margin-top: 8px;
}

#code-display {
    font-family: 'SF Mono', 'Fira Code', monospace;
    font-size: 64px;
    font-weight: 700;
    letter-spacing: 12px;
    color: #4ade80;
    padding: 24px 0;
    user-select: all;
}

#countdown {
    position: relative;
    height: 32px;
    background: #0d0d0d;
    border-radius: 16px;
    overflow: hidden;
    margin-bottom: 8px;
}

#countdown-bar {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background: linear-gradient(90deg, #4ade80, #22c55e);
    border-radius: 16px;
    transition: width 1s linear;
}

#countdown-text {
    position: relative;
    z-index: 1;
    line-height: 32px;
    font-size: 14px;
    font-weight: 600;
    color: #000;
}

.hidden {
    display: none;
}

.error {
    border-color: #ef4444 !important;
}

@media (max-width: 480px) {
    .container {
        margin: 16px;
        padding: 24px;
    }

    #code-display {
        font-size: 48px;
        letter-spacing: 8px;
    }
}