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

:root {
    --primary: #0a1628;
    --secondary: #1a2744;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --error: #ef4444;
    --success: #22c55e;
    --border: #334155;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--primary);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(ellipse at 20% 20%, rgba(59, 130, 246, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 80%, rgba(59, 130, 246, 0.1) 0%, transparent 50%),
        linear-gradient(180deg, var(--primary) 0%, #0d1a30 100%);
    z-index: -1;
}

header {
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border);
    background: rgba(10, 22, 40, 0.8);
    backdrop-filter: blur(10px);
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--accent) 0%, #1d4ed8 100%);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.25rem;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.025em;
}

main {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.container {
    width: 100%;
    max-width: 440px;
}

.hero {
    text-align: center;
    margin-bottom: 2rem;
}

.hero h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    letter-spacing: -0.025em;
}

.hero p {
    color: var(--text-muted);
    font-size: 1rem;
    line-height: 1.6;
}

.security-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(34, 197, 94, 0.1);
    border: 1px solid rgba(34, 197, 94, 0.3);
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    color: var(--success);
    margin-bottom: 1.5rem;
}

.card {
    background: var(--secondary);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.tabs {
    display: flex;
    gap: 0;
    margin-bottom: 1.5rem;
    background: var(--primary);
    padding: 0.25rem;
    border-radius: 10px;
}

.tab {
    flex: 1;
    padding: 0.75rem;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-size: 0.9375rem;
    font-weight: 500;
    cursor: pointer;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.tab.active {
    background: var(--accent);
    color: white;
}

.tab:not(.active):hover {
    color: var(--text);
    background: rgba(255, 255, 255, 0.05);
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.form-input {
    width: 100%;
    padding: 0.875rem 1rem;
    background: var(--primary);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text);
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.form-input::placeholder {
    color: var(--text-muted);
}

.btn {
    width: 100%;
    padding: 1rem;
    background: var(--accent);
    border: none;
    border-radius: 10px;
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.btn:hover {
    background: var(--accent-hover);
}

.btn:active {
    transform: scale(0.98);
}

.alert {
    padding: 1rem;
    border-radius: 10px;
    margin-bottom: 1.25rem;
    font-size: 0.9375rem;
    display: none;
}

.alert.error {
    display: block;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: var(--error);
}

.divider {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 1.5rem 0;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.divider::before,
.divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

.info-text {
    font-size: 0.875rem;
    color: var(--text-muted);
    text-align: center;
    line-height: 1.6;
}

.code-input {
    font-family: 'Courier New', monospace;
    letter-spacing: 0.25em;
    text-transform: uppercase;
}

footer {
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--border);
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.shake {
    animation: shake 0.3s ease-in-out;
}