:root {
    --primary: #4f46e5;
    --primary-light: #eef2ff;
    --primary-hover: #4338ca;
    --surface: #ffffff;
    --bg: #f8f9fb;
    --border: #e5e7eb;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --success: #059669;
    --danger: #dc2626;
    --radius-md: 8px;
    --radius-lg: 12px;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.1);
}

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

body {
    font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    -webkit-font-smoothing: antialiased;
}

.login-container {
    background: var(--surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    padding: 52px 44px;
    max-width: 420px;
    width: 90%;
    text-align: center;
}

.logo {
    font-size: 1.5rem;
    color: var(--primary);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 20px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 36px;
    line-height: 1.5;
}

.oauth-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 11px 24px;
    font-size: 0.9rem;
    font-family: inherit;
    font-weight: 500;
    color: var(--text-primary);
    text-decoration: none;
    transition: all 0.15s ease;
    cursor: pointer;
    width: 100%;
    max-width: 280px;
}

.oauth-btn:hover {
    border-color: var(--text-muted);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.microsoft-signin-btn {
    margin-top: 12px;
}

.oauth-icon {
    width: 18px;
    height: 18px;
    margin-right: 10px;
}

.error-message {
    background: #fef2f2;
    color: var(--danger);
    padding: 10px 16px;
    border-radius: var(--radius-md);
    border: 1px solid #fecaca;
    margin-bottom: 20px;
    font-size: 0.85rem;
    display: none;
}

.help-text {
    margin-top: 16px;
    color: var(--text-muted);
    font-size: 0.8rem;
}

.help-text a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

.help-text a:hover {
    text-decoration: underline;
}

.footer {
    margin-top: 32px;
    color: var(--text-muted);
    font-size: 0.8rem;
}

/* Loading state */
.loading {
    display: none;
    color: var(--primary);
    margin-top: 16px;
    font-size: 0.85rem;
}

.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid var(--border);
    border-top: 2px solid var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-right: 8px;
    vertical-align: middle;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.copyright {
    margin-top: 24px;
    color: var(--text-muted);
    font-size: 0.75rem;
    text-align: center;
}

/* Mobile */
@media (max-width: 480px) {
    .login-container {
        padding: 36px 24px;
        width: 95%;
    }

    .subtitle {
        font-size: 0.85rem;
    }
}