/* ===== Reset & Base ===== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg-grad-1: #667eea;
    --bg-grad-2: #764ba2;
    --surface: #ffffff;
    --surface-alt: #f8f9fc;
    --border: #e6e8ef;
    --text: #1f2937;
    --text-soft: #6b7280;
    --text-muted: #9ca3af;
    --income: #10b981;
    --income-bg: #d1fae5;
    --expense: #ef4444;
    --expense-bg: #fee2e2;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
    --radius: 14px;
    --radius-sm: 8px;
}

html,
body {
    height: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
        Arial, sans-serif;
    color: var(--text);
    background: linear-gradient(135deg, var(--bg-grad-1) 0%, var(--bg-grad-2) 100%);
    background-attachment: fixed;
    min-height: 100vh;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    padding: 24px 16px;
}

/* ===== Layout ===== */
.app {
    max-width: 880px;
    margin: 0 auto;
}

.header {
    text-align: center;
    color: #fff;
    margin-bottom: 28px;
    padding: 8px 0;
}

.logo {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 6px;
}

.subtitle {
    font-size: 1rem;
    opacity: 0.9;
}

.main {
    display: grid;
    gap: 20px;
}

.footer {
    text-align: center;
    color: rgba(255, 255, 255, 0.85);
    font-size: 0.85rem;
    margin-top: 28px;
}

/* ===== Cards / Summary ===== */
.summary {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    gap: 6px;
    position: relative;
    overflow: hidden;
}

.card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary);
}

.card-balance::before {
    background: linear-gradient(90deg, #6366f1, #8b5cf6);
}
.card-income::before {
    background: var(--income);
}
.card-expense::before {
    background: var(--expense);
}

.card-label {
    font-size: 0.78rem;
    color: var(--text-soft);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

.card-amount {
    font-size: 1.7rem;
    font-weight: 700;
    color: var(--text);
    letter-spacing: -0.5px;
}

#totalIncome {
    color: var(--income);
}
#totalExpense {
    color: var(--expense);
}

/* ===== Form ===== */
.form-section,
.history-section {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow-md);
}

.section-title {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 16px;
}

.transaction-form {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 14px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group label {
    font-size: 0.82rem;
    color: var(--text-soft);
    font-weight: 600;
}

.form-group input,
.form-group select {
    font-family: inherit;
    font-size: 0.95rem;
    padding: 10px 12px;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--surface-alt);
    color: var(--text);
    transition: border-color 0.15s, box-shadow 0.15s, background 0.15s;
}

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

/* Hide number input spinners for cleaner look */
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
input[type="number"] {
    -moz-appearance: textfield;
}

/* ===== Buttons ===== */
.btn {
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    padding: 12px 18px;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: background 0.15s, transform 0.05s, box-shadow 0.15s;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
    align-self: flex-start;
    box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    background: var(--primary-hover);
    box-shadow: 0 6px 14px rgba(99, 102, 241, 0.4);
}

.btn-primary:active {
    transform: translateY(1px);
}

/* ===== Filter buttons ===== */
.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 16px;
}

.history-header .section-title {
    margin-bottom: 0;
}

.filter-group {
    display: inline-flex;
    background: var(--surface-alt);
    border-radius: 10px;
    padding: 4px;
    gap: 2px;
}

.filter-btn {
    font-family: inherit;
    font-size: 0.85rem;
    font-weight: 600;
    padding: 7px 14px;
    border: none;
    border-radius: 7px;
    background: transparent;
    color: var(--text-soft);
    cursor: pointer;
    transition: background 0.15s, color 0.15s;
}

.filter-btn:hover {
    color: var(--text);
}

.filter-btn.active {
    background: #fff;
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}

/* ===== Transaction list ===== */
.transaction-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.transaction-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 16px;
    background: var(--surface-alt);
    border-radius: var(--radius-sm);
    border-left: 4px solid var(--border);
    transition: background 0.15s, transform 0.1s;
}

.transaction-item:hover {
    background: #f1f3f9;
}

.transaction-item.income {
    border-left-color: var(--income);
}

.transaction-item.expense {
    border-left-color: var(--expense);
}

.txn-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.transaction-item.income .txn-icon {
    background: var(--income-bg);
    color: var(--income);
}
.transaction-item.expense .txn-icon {
    background: var(--expense-bg);
    color: var(--expense);
}

.txn-body {
    flex: 1;
    min-width: 0;
}

.txn-desc {
    font-weight: 600;
    color: var(--text);
    margin-bottom: 2px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.txn-meta {
    font-size: 0.8rem;
    color: var(--text-muted);
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.txn-meta .badge {
    background: #e0e7ff;
    color: #4338ca;
    padding: 1px 8px;
    border-radius: 999px;
    font-weight: 600;
    font-size: 0.72rem;
}

.txn-amount {
    font-weight: 700;
    font-size: 1rem;
    white-space: nowrap;
}

.transaction-item.income .txn-amount {
    color: var(--income);
}
.transaction-item.expense .txn-amount {
    color: var(--expense);
}

.txn-delete {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1.1rem;
    cursor: pointer;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    transition: background 0.15s, color 0.15s;
    flex-shrink: 0;
}

.txn-delete:hover {
    background: var(--expense-bg);
    color: var(--expense);
}

/* ===== Empty state ===== */
.empty-state {
    text-align: center;
    padding: 36px 16px;
    color: var(--text-soft);
}

.empty-icon {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.empty-state p {
    font-weight: 600;
    color: var(--text);
    margin-bottom: 4px;
}

.empty-state span {
    font-size: 0.9rem;
}

.hidden {
    display: none !important;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
    body {
        padding: 16px 10px;
    }

    .logo {
        font-size: 1.5rem;
    }

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

    .card-amount {
        font-size: 1.4rem;
    }

    .form-section,
    .history-section {
        padding: 18px;
    }

    .history-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .transaction-item {
        padding: 12px;
    }

    .txn-meta {
        font-size: 0.75rem;
    }
}