:root {
    /* Blaus primaris i d'accent */
    --primary-color: #2563eb;       /* Blau vibrant modern */
    --primary-dark: #1d4ed8;        /* Blau més intens per a 'hover' */
    --primary-soft: #eff6ff;        /* Blau molt clar per a fons o seleccionats */

    /* Perill / Alerta (més clar i contingut) */
    --danger-color: #ef4444;
    --danger-soft: #fef2f2;

    /* Informació / Accents secundaris */
    --info-color: #0284c7;         /* Blau cel/cian */
    --info-soft: #f0f9ff;

    /* Neutres i fons (transició de fons càlid a fred) */
    --bg-color: #f8fafc;           /* Fons principal gris-blau molt suau */
    --card-bg: #ffffff;
    --text-dark: #0f172a;          /* Text fosc amb matís blau nit */
    --text-light: #64748b;         /* Text secundari neutre */
    --border-color: #e2e8f0;       /* Vores fines i netes */

    /* Ombres subtils i difuminades */
    --shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.08);
    --shadow-hover: 0 20px 35px -5px rgba(15, 23, 42, 0.12);
    --focus-ring: rgba(37, 99, 235, 0.25);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background:
        linear-gradient(135deg, rgba(37, 99, 235, 0.11), transparent 34%),
        linear-gradient(180deg, #ffffff 0%, var(--bg-color) 100%);
    color: var(--text-dark);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 450px;
}

.login-card {
    background: var(--card-bg);
    border: 1px solid rgba(37, 99, 235, 0.12);
    border-radius: 14px;
    box-shadow: var(--shadow);
    padding: 42px;
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.header {
    text-align: center;
    margin-bottom: 32px;
}

.header h1 {
    color: var(--text-dark);
    font-size: 1.75rem;
    font-weight: 750;
    line-height: 1.2;
    margin-bottom: 8px;
}

.header .subtitle {
    color: var(--text-light);
    font-size: 0.95rem;
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    color: var(--text-dark);
    font-weight: 650;
    font-size: 0.9rem;
}

.form-group input {
    padding: 12px 14px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-dark);
    font-size: 1rem;
    transition: border-color 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px var(--focus-ring);
    background-color: #f8fbff;
}

.error-message {
    background-color: var(--danger-soft);
    color: var(--danger-color);
    padding: 12px 16px;
    border-radius: 8px;
    border-left: 4px solid var(--danger-color);
    font-size: 14px;
    animation: shake 0.3s ease-in-out;
}

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

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    padding: 14px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.18s ease, box-shadow 0.18s ease, transform 0.18s ease;
    margin-top: 8px;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

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

.btn-primary:focus-visible {
    outline: 3px solid var(--focus-ring);
    outline-offset: 2px;
}

.btn-primary:disabled {
    background-color: #94a3b8;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.info-box {
    background-color: var(--info-soft);
    border-left: 4px solid var(--info-color);
    padding: 16px;
    border-radius: 8px;
    margin-top: 24px;
}

.info-box p {
    color: var(--text-dark);
    font-size: 13px;
    margin-bottom: 8px;
}

.info-box p:last-child {
    margin-bottom: 0;
}

.info-box code {
    background-color: #ffffff;
    padding: 2px 8px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--danger-color);
    font-weight: 600;
}

.footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-light);
    font-size: 12px;
}

/* Responsive */
@media (max-width: 480px) {
    .login-card {
        padding: 28px 22px;
    }

    .header h1 {
        font-size: 1.45rem;
    }
}

/* Loading spinner */
.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-left: 8px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}