:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --success-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --danger-gradient: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
    --dark-bg: #0f172a;
    --card-bg: #1e293b;
    --card-border: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
    --shadow-hover: 0 25px 80px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--dark-bg);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(102, 126, 234, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(118, 75, 162, 0.1) 0%, transparent 50%);
    z-index: -1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInDown 0.6s ease-out;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.logo h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Card Styles */
.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 1.5rem;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.card-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.badge {
    background: var(--success-gradient);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.875rem;
    font-weight: 600;
}

/* Input Group */
.input-group {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

input[type="text"] {
    flex: 1;
    min-width: 300px;
    padding: 1rem 1.5rem;
    background: var(--dark-bg);
    border: 2px solid var(--card-border);
    border-radius: 1rem;
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.3s ease;
}

input[type="text"]:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

input[type="text"]::placeholder {
    color: var(--text-muted);
}

/* Digits selector */
.digits-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.digits-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.digits-select {
    padding: 0.5rem 1rem;
    background: var(--dark-bg);
    border: 1px solid var(--card-border);
    border-radius: 0.5rem;
    color: var(--text-primary);
    font-size: 0.95rem;
    cursor: pointer;
}

.digits-select:focus {
    outline: none;
    border-color: #667eea;
}

.hint {
    color: var(--text-muted);
    font-size: 0.875rem;
    text-align: center;
}

/* Button Styles */
.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 1rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    white-space: nowrap;
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--dark-bg);
    color: var(--text-secondary);
    border: 1px solid var(--card-border);
}

.btn-secondary:hover {
    color: var(--text-primary);
    border-color: #667eea;
    background: rgba(102, 126, 234, 0.1);
}

.btn-icon {
    padding: 0.75rem;
    background: var(--dark-bg);
    color: var(--text-secondary);
}

.btn-icon:hover {
    color: var(--text-primary);
    background: var(--card-border);
}

/* Code Display */
.code-display {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    margin-bottom: 2rem;
    padding: 2rem;
    background: var(--dark-bg);
    border-radius: 1rem;
}

.code {
    font-size: 4rem;
    font-weight: 700;
    font-family: 'Courier New', monospace;
    letter-spacing: 0.5rem;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: pulse 2s ease-in-out infinite;
}

.code.code-8 {
    font-size: 2.75rem;
    letter-spacing: 0.35rem;
}

/* Timer Ring */
.timer-container {
    position: relative;
    width: 60px;
    height: 60px;
}

.timer-ring {
    transform: rotate(-90deg);
}

.timer-ring-bg {
    fill: none;
    stroke: var(--card-border);
    stroke-width: 4;
}

.timer-ring-progress {
    fill: none;
    stroke: url(#timerGradient);
    stroke-width: 4;
    stroke-linecap: round;
    transition: stroke-dashoffset 1s linear;
}

.timer-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Stats */
.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.stat {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding: 1rem;
    background: var(--dark-bg);
    border-radius: 1rem;
    text-align: center;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-value {
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 600;
}

/* Error Card */
.error-card {
    text-align: center;
    border-color: #fee140;
}

.error-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.error-card h3 {
    margin-bottom: 0.5rem;
    color: #fee140;
}

.error-card p {
    color: var(--text-secondary);
}

/* Footer / API Docs */
.footer {
    margin-top: 4rem;
}

.api-info-banner {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.5rem;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
    border: 1px solid rgba(102, 126, 234, 0.3);
    border-radius: 1rem;
    margin-bottom: 2rem;
}

.info-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.info-text {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.info-text strong {
    color: var(--text-primary);
    font-size: 1rem;
}

.info-text span {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-family: 'Courier New', monospace;
}

.api-docs {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 1.5rem;
    padding: 2rem;
}

.api-docs h3 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    text-align: center;
}

.api-note {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    padding: 1rem;
    background: var(--dark-bg);
    border-radius: 0.5rem;
}

.api-section {
    margin-bottom: 2rem;
}

.api-section h4 {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.code-block {
    display: block;
    padding: 1.5rem;
    background: var(--dark-bg);
    border: 1px solid var(--card-border);
    border-radius: 1rem;
    color: var(--text-primary);
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    overflow-x: auto;
    white-space: pre;
    line-height: 1.6;
}

/* Animations */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.8;
    }
}

.input-card {
    animation: fadeInDown 0.6s ease-out 0.1s both;
}

.result-card {
    animation: fadeInDown 0.6s ease-out 0.2s both;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }

    .logo h1 {
        font-size: 2rem;
    }

    .input-group {
        flex-direction: column;
    }

    input[type="text"] {
        min-width: 100%;
    }

    .code {
        font-size: 2.5rem;
        letter-spacing: 0.25rem;
    }

    .code-display {
        flex-direction: column;
        text-align: center;
    }

    .stats {
        grid-template-columns: 1fr;
    }
}

/* SVG Gradient Definition */
svg defs {
    position: absolute;
}