:root {
    --bg-gradient-start: #0f172a;
    --bg-gradient-end: #1e293b;
    --card-bg: rgba(255, 255, 255, 0.96);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --border: #cbd5e1;
    --input-focus: rgba(37, 99, 235, 0.25);
    --shadow: 0 18px 45px rgba(2, 6, 23, 0.25);
    --error-bg: #fee2e2;
    --error-border: #fca5a5;
    --error-text: #991b1b;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 24px;
    font-family: "Segoe UI", Roboto, Arial, sans-serif;
    background: linear-gradient(145deg, var(--bg-gradient-start), var(--bg-gradient-end));
    color: var(--text-primary);
}

.login-card {
    width: min(100%, 420px);
    background: var(--card-bg);
    border-radius: 16px;
    padding: 28px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(4px);
}

h2 {
    margin: 0 0 8px;
    font-size: 1.65rem;
    line-height: 1.2;
    text-align: center;
}

.subtitle {
    margin: 0 0 24px;
    font-size: 0.95rem;
    color: var(--text-secondary);
    text-align: center;
}

.error-message {
    margin: 0 0 16px;
    padding: 10px 12px;
    border: 1px solid var(--error-border);
    border-radius: 10px;
    background: var(--error-bg);
    color: var(--error-text);
    font-size: 0.92rem;
    font-weight: 600;
}

form {
    display: grid;
    gap: 14px;
}

label {
    font-size: 0.92rem;
    font-weight: 600;
    margin-bottom: -6px;
}

input {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 4px var(--input-focus);
}

button {
    margin-top: 8px;
    width: 100%;
    border: 0;
    border-radius: 10px;
    padding: 12px 14px;
    background: var(--accent);
    color: #ffffff;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.06s ease;
}

button:hover {
    background: var(--accent-hover);
}

button:active {
    transform: translateY(1px);
}

@media (max-width: 480px) {
    body {
        padding: 16px;
    }

    .login-card {
        padding: 22px;
        border-radius: 14px;
    }

    h2 {
        font-size: 1.45rem;
    }
}