:root {
    --bg-color: #0f0f11;
    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --input-bg: #18181b;
    --border-color: #27272a;
    --error-color: #ef4444;
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

.kiden {
    color: var(--bg-color);
}

.kiden::selection {
    background: var(--text-primary);
    color: var(--bg-color);
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-family);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 2rem;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 600px;
    width: 100%;
    text-align: left;
    animation: fadeIn 0.8s ease-out;
}

h1 {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    margin-bottom: 1.5rem;
    line-height: 1.1;
    background: linear-gradient(to right, #fff, #999);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-weight: 400;
}

p:last-of-type {
    margin-bottom: 3rem;
}

.input-group {
    display: flex;
    gap: 1rem;
    flex-direction: row;
}

input[type="text"] {
    flex: 1;
    padding: 1rem 1.25rem;
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1rem;
    outline: none;
    transition: all 0.3s ease;
}

input[type="text"]:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
}

button {
    padding: 1rem 2rem;
    background-color: var(--text-primary);
    color: var(--bg-color);
    border: none;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(255, 255, 255, 0.1);
    background-color: #e4e4e7;
}

button:active {
    transform: translateY(0);
}

#error-message {
    margin-top: 1rem;
    color: var(--error-color);
    font-size: 0.9rem;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    min-height: 1.5em;
}

#error-message.visible {
    opacity: 1;
    transform: translateY(0);
}

@keyframes shake {

    10%,
    90% {
        transform: translate3d(-1px, 0, 0);
    }

    20%,
    80% {
        transform: translate3d(2px, 0, 0);
    }

    30%,
    50%,
    70% {
        transform: translate3d(-4px, 0, 0);
    }

    40%,
    60% {
        transform: translate3d(4px, 0, 0);
    }
}

@media (max-width: 640px) {
    h1 {
        font-size: 2.5rem;
    }

    p {
        font-size: 1.1rem;
    }

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

    button {
        width: 100%;
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}