:root {
    --primary: #4a90e2;
    --success: #2ecc71;
    --danger: #e74c3c;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --text-main: #333333;
    --text-muted: #777777;
    --border-color: #eeeeee;
    --tag-bg: #f1f3f5;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    --border-radius: 12px;
    color-scheme: light;
}

:root[data-theme="dark"] {
    --bg-color: #171a21;
    --card-bg: #222731;
    --text-main: #e8ebf0;
    --text-muted: #a7afbd;
    --border-color: #363d49;
    --tag-bg: #343c49;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    color-scheme: dark;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
}

.container {
    max-width: 1000px;
    margin: 40px auto;
    padding: 0 20px;
}

header {
    position: relative;
    text-align: center;
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 8px;
}

header .subtitle {
    color: var(--text-muted);
}

.theme-toggle {
    position: absolute;
    top: 8px;
    right: 0;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--card-bg);
    color: var(--text-main);
    font: inherit;
    cursor: pointer;
}

.theme-toggle:hover {
    border-color: var(--primary);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

.summary-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.card {
    background-color: var(--card-bg);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.summary-cards .card h3 {
    font-size: 0.9rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 12px;
}

.summary-cards .card p {
    font-size: 1.8rem;
    font-weight: 700;
}

.card.balance p { color: var(--primary); }
.card.income p { color: var(--success); }
.card.expense p { color: var(--danger); }

.main-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 30px;
}

@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
    }
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.btn-primary {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 10px 18px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: opacity 0.2s;
}

.btn-primary:hover {
    opacity: 0.9;
}

.transaction-list {
    list-style: none;
}

.transaction-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
}

.transaction-item:last-child {
    border-bottom: none;
}

.transaction-info h4 {
    font-size: 1rem;
    margin-bottom: 4px;
}

.transaction-info span {
    font-size: 0.85rem;
    color: var(--text-muted);
    background: var(--tag-bg);
    padding: 2px 8px;
    border-radius: 4px;
}

.transaction-amount {
    font-weight: 600;
}

.transaction-amount.plus { color: var(--success); }
.transaction-amount.minus { color: var(--danger); }

.delete-btn {
    background: none;
    border: none;
    color: #ccc;
    cursor: pointer;
    margin-left: 15px;
    transition: color 0.2s;
}

.delete-btn:hover {
    color: var(--danger);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: var(--card-bg);
    margin: 10% auto;
    padding: 30px;
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 450px;
    position: relative;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
}

.close-btn {
    position: absolute;
    right: 20px;
    top: 15px;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-muted);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.form-group input, .form-group select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-family: inherit;
    background-color: var(--card-bg);
    color: var(--text-main);
}

.btn-block {
    width: 100%;
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 14px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 10px;
}

.chart-container {
    position: relative;
    height: 300px;
    width: 100%;
}

@media (max-width: 600px) {
    header {
        padding-top: 52px;
    }

    .theme-toggle {
        top: 0;
        right: 50%;
        transform: translateX(50%);
    }
}