:root {
    --bg: #0a0e1a;
    --surface: #151b2e;
    --accent: #00ff88;
    --accent-glow: rgba(0, 255, 136, 0.2);
    --text: #e8edf5;
    --text-dim: #7a8396;
    --border: #2a3447;
    --error: #ff4466;
}

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

body {
    font-family: 'JetBrains Mono', monospace;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    position: relative;
    overflow-x: hidden;
}

/* Animated grid background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 50px 50px;
    opacity: 0.3;
    animation: gridMove 20s linear infinite;
    z-index: 0;
}

@keyframes gridMove {
    0% {
        transform: translate(0, 0);
    }
    100% {
        transform: translate(50px, 50px);
    }
}

.container {
    max-width: 600px;
    width: 100%;
    position: relative;
    z-index: 1;
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.header {
    text-align: center;
    margin-bottom: 3rem;
}

h1 {
    font-family: 'Orbitron', sans-serif;
    font-size: 3rem;
    font-weight: 900;
    color: var(--accent);
    text-shadow: 0 0 30px var(--accent-glow);
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
    animation: flicker 3s ease-in-out infinite;
}

@keyframes flicker {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.95; }
}

.subtitle {
    color: var(--text-dim);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.2em;
}

.card {
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: 16px;
    padding: 2.5rem;
    position: relative;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

.form-group {
    margin-bottom: 2rem;
}

label {
    display: block;
    margin-bottom: 0.75rem;
    color: var(--accent);
    font-weight: 700;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

input[type="url"],
input[type="number"] {
    width: 100%;
    padding: 1rem;
    background: var(--bg);
    border: 2px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

input[type="url"]:focus,
input[type="number"]:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 4px var(--accent-glow);
}

input[type="url"]::placeholder,
input[type="number"]::placeholder {
    color: var(--text-dim);
}

.button-group {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

button {
    flex: 1;
    padding: 1rem 2rem;
    background: var(--accent);
    color: var(--bg);
    border: none;
    border-radius: 8px;
    font-family: 'Orbitron', sans-serif;
    font-weight: 700;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    transition: all 0.3s ease;
}

#downloadBtn {
    background: var(--accent);
    border: 2px solid var(--accent);
    color: var(--bg);
}

#downloadBtn:hover {
    background: transparent;
    color: var(--accent);
}

button:active {
    opacity: 0.8;
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

button span {
    position: relative;
    z-index: 1;
}

.preview {
    margin-top: 2rem;
    padding: 2rem;
    background: var(--bg);
    border: 2px dashed var(--border);
    border-radius: 8px;
    text-align: center;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transform: scale(0.95);
    transition: all 0.4s ease;
}

.preview.active {
    opacity: 1;
    transform: scale(1);
}

#qrCanvas {
    max-width: 100%;
    height: auto;
    image-rendering: pixelated;
    border: 2px solid var(--accent);
    background: white;
}

.preview-label {
    margin-top: 1rem;
    color: var(--text-dim);
    font-size: 0.75rem;
}

.error {
    color: var(--error);
    font-size: 0.875rem;
    margin-top: 0.5rem;
    display: none;
}

.error.show {
    display: block;
    animation: shake 0.4s ease;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

.specs {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--bg);
    border-left: 3px solid var(--accent);
    font-size: 0.75rem;
    color: var(--text-dim);
    line-height: 1.8;
}

.specs strong {
    color: var(--accent);
}

.footer {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.8rem;
    color: var(--text-dim);
}

.footer-links {
    display: flex;
    gap: 8px;
    align-items: center;
}

.footer a {
    color: var(--accent);
    text-decoration: none;
    transition: opacity 0.2s ease;
}

.footer a:hover {
    text-decoration: underline;
    opacity: 0.8;
}