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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1rem 0;
    box-shadow: var(--shadow-lg);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 1.5rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 0.4rem 0.9rem;
    border-radius: 0.5rem;
    transition: background 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    background-color: rgba(255, 255, 255, 0.2);
}

main {
    flex: 1;
    padding: 2rem 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.hero {
    text-align: center;
    margin-bottom: 2.5rem;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    color: transparent;
}

.hero p {
    color: var(--text-secondary);
    font-size: 1.2rem;
}

.app-container {
    display: grid;
    grid-template-columns: 1fr 1.4fr;
    gap: 2rem;
}

.expense-form-section,
.expenses-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.expense-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.form-group label {
    font-weight: 600;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.8rem;
    border: 2px solid var(--border-color);
    border-radius: 0.6rem;
    font-size: 1rem;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.btn {
    padding: 0.9rem 1.5rem;
    border: none;
    border-radius: 0.6rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.btn-secondary {
    background-color: var(--border-color);
    color: var(--text-primary);
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.summary-cards {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.summary-card {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1.5rem;
    border-radius: 0.8rem;
    text-align: center;
}

.filters {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}

.expenses-container {
    max-height: 450px;
    overflow-y: auto;
}

.expense-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.75rem;
    margin-bottom: 0.8rem;
    background-color: var(--bg-color);
    gap: 1rem;
}

.expense-item-category {
    display: inline-block;
    padding: 0.2rem 0.7rem;
    background-color: var(--primary-color);
    color: white;
    border-radius: 999px;
    font-size: 0.8rem;
    margin-top: 0.4rem;
}

.expense-item-amount {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--danger-color);
}

.empty-state {
    text-align: center;
    color: var(--text-secondary);
    padding: 2rem;
}

footer {
    background-color: var(--text-primary);
    color: white;
    padding: 1.5rem 0;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
    padding: 0 2rem;
}

.footer-container a {
    color: white;
    text-decoration: underline;
}

.delete-container,
.privacy-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    background: var(--card-bg);
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.delete-container h2 {
    color: var(--danger-color);
}

.privacy-container h2 {
    color: var(--primary-color);
}

.danger-card {
    border: 2px solid var(--danger-color);
    border-radius: 1rem;
    padding: 1.5rem;
    background-color: #fef2f2;
    margin-bottom: 1.5rem;
}

.account-delete-form {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.checkbox-group {
    flex-direction: row;
    align-items: center;
    gap: 0.75rem;
}

.status-message {
    min-height: 1.5rem;
    font-weight: 600;
}

.status-success {
    color: var(--success-color);
}

.status-error {
    color: var(--danger-color);
}

@media (max-width: 900px) {
    .app-container {
        grid-template-columns: 1fr;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .summary-cards {
        grid-template-columns: 1fr;
    }
}