:root {
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-success: #22c55e;
    --color-warning: #f97316;
    --color-danger: #dc2626;
    --color-background: #f8fafc;
    --color-card: #ffffff;
    --color-text: #1e293b;
    --color-muted: #64748b;
    --color-border: #dbe3ef;
    --shadow-card: 0 12px 30px rgba(15, 23, 42, 0.08);
    --radius-card: 12px;
    --radius-control: 10px;
    --container: 1040px;
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
}

body {
    min-height: 100%;
    margin: 0;
    background: var(--color-background);
    color: var(--color-text);
    font-family: "Nunito", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    font-size: 16px;
    line-height: 1.5;
}

a {
    color: var(--color-primary-dark);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

button,
input,
textarea,
select {
    font: inherit;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 64px;
    padding: 12px 18px;
    background: var(--color-card);
    border-bottom: 1px solid var(--color-border);
}

.brand {
    color: var(--color-text);
    font-size: 1.15rem;
    font-weight: 800;
    letter-spacing: 0;
}

.brand:hover {
    text-decoration: none;
}

.nav-toggle {
    display: inline-flex;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
    width: 44px;
    height: 44px;
    padding: 0;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-control);
    background: var(--color-card);
    cursor: pointer;
}

.nav-toggle span:not(.sr-only) {
    display: block;
    width: 20px;
    height: 2px;
    margin: 0 auto;
    background: var(--color-text);
    border-radius: 999px;
}

.main-nav {
    position: absolute;
    top: 64px;
    right: 18px;
    left: 18px;
    display: none;
    flex-direction: column;
    gap: 6px;
    padding: 10px;
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-card);
}

.main-nav.is-open {
    display: flex;
}

.main-nav a {
    display: flex;
    align-items: center;
    min-height: 44px;
    padding: 10px 12px;
    color: var(--color-text);
    font-weight: 700;
    border-radius: 8px;
}

.main-nav a:hover {
    background: #eff6ff;
    color: var(--color-primary-dark);
    text-decoration: none;
}

.page-shell {
    width: min(100%, var(--container));
    margin: 0 auto;
    padding: 24px 16px 44px;
}

.site-footer {
    padding: 24px 16px 32px;
    color: var(--color-muted);
    text-align: center;
}

.panel,
.card {
    background: var(--color-card);
    border: 1px solid rgba(219, 227, 239, 0.9);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-card);
}

.panel {
    padding: 22px;
}

.auth-panel {
    max-width: 480px;
    margin: 0 auto;
}

.card {
    padding: 18px;
}

.stack {
    display: grid;
    gap: 16px;
}

.grid {
    display: grid;
    gap: 16px;
}

.metric-grid {
    display: grid;
    gap: 12px;
}

.metric {
    padding: 18px;
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-card);
}

.metric-label {
    display: block;
    color: var(--color-muted);
    font-size: 0.92rem;
    font-weight: 700;
}

.metric-value {
    display: block;
    margin-top: 4px;
    font-size: 1.85rem;
    font-weight: 800;
    letter-spacing: 0;
}

.expense-list {
    display: grid;
    gap: 12px;
}

.expense-card {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
}

.expense-card strong,
.expense-card span {
    display: block;
}

.expense-amount {
    flex: 0 0 auto;
    color: var(--color-primary-dark);
    font-size: 1.08rem;
    font-weight: 800;
}

.section-head {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 16px;
}

.section-head h2 {
    margin-bottom: 0;
}

.section-head form {
    display: inline-flex;
}

.budget-form {
    max-width: 520px;
}

.row-open td {
    background: #fff7ed;
}

h1,
h2,
h3 {
    margin: 0 0 14px;
    line-height: 1.2;
    letter-spacing: 0;
}

h1 {
    font-size: 1.8rem;
}

h2 {
    font-size: 1.35rem;
}

p {
    margin: 0 0 14px;
}

form {
    display: grid;
    gap: 16px;
}

.form-row {
    display: grid;
    gap: 8px;
}

.inline-form {
    align-items: end;
}

.form-note {
    margin: 16px 0 0;
}

label {
    font-weight: 800;
}

input,
textarea,
select {
    width: 100%;
    min-height: 48px;
    padding: 14px 16px;
    color: var(--color-text);
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-control);
    outline: none;
}

textarea {
    min-height: 130px;
    resize: vertical;
}

input:focus,
textarea:focus,
select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.15);
}

.button,
button,
input[type="submit"] {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 12px 18px;
    color: #ffffff;
    font-weight: 800;
    background: var(--color-primary);
    border: 0;
    border-radius: var(--radius-control);
    cursor: pointer;
    transition: background-color 140ms ease, transform 140ms ease;
}

.button:hover,
button:hover,
input[type="submit"]:hover {
    background: var(--color-primary-dark);
    text-decoration: none;
}

.button:active,
button:active,
input[type="submit"]:active {
    transform: translateY(1px);
}

.button-secondary {
    color: var(--color-text);
    background: #e2e8f0;
}

.button-secondary:hover {
    background: #cbd5e1;
}

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

.button-danger:hover {
    background: #b91c1c;
}

.badge {
    display: inline-flex;
    align-items: center;
    min-height: 28px;
    padding: 4px 10px;
    color: #ffffff;
    font-size: 0.86rem;
    font-weight: 800;
    border-radius: 999px;
}

.badge-open {
    background: var(--color-warning);
}

.badge-paid {
    background: var(--color-success);
}

.action-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.action-list form {
    display: inline-flex;
}

.action-list button {
    min-height: 38px;
    padding: 8px 12px;
    font-size: 0.92rem;
}

.muted {
    color: var(--color-muted);
}

.alert {
    padding: 14px 16px;
    border-radius: var(--radius-control);
    border: 1px solid var(--color-border);
    background: #eff6ff;
    color: var(--color-text);
}

.alert-success {
    background: #ecfdf5;
    border-color: #bbf7d0;
}

.alert-error {
    background: #fef2f2;
    border-color: #fecaca;
}

.responsive-table {
    width: 100%;
    border-collapse: collapse;
}

.responsive-table thead {
    display: none;
}

.responsive-table,
.responsive-table tbody,
.responsive-table tr,
.responsive-table td {
    display: block;
}

.responsive-table tr {
    margin-bottom: 12px;
    padding: 14px;
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-card);
}

.responsive-table td {
    display: grid;
    grid-template-columns: minmax(110px, 38%) 1fr;
    gap: 10px;
    padding: 8px 0;
}

.responsive-table td::before {
    content: attr(data-label);
    color: var(--color-muted);
    font-weight: 800;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

@media (min-width: 720px) {
    .site-header {
        padding: 14px 28px;
    }

    .nav-toggle {
        display: none;
    }

    .main-nav {
        position: static;
        display: flex;
        flex-direction: row;
        align-items: center;
        gap: 8px;
        padding: 0;
        border: 0;
        box-shadow: none;
    }

    .main-nav a {
        padding: 8px 12px;
    }

    .page-shell {
        padding: 36px 24px 56px;
    }

    .grid,
    .metric-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .panel {
        padding: 28px;
    }

    .inline-form {
        grid-template-columns: minmax(0, 1fr) minmax(0, 1fr) auto;
    }

    .budget-form {
        grid-template-columns: minmax(0, 1fr) auto;
    }

    .section-head {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }

    h1 {
        font-size: 2.2rem;
    }

    .responsive-table {
        display: table;
        background: var(--color-card);
        border: 1px solid var(--color-border);
        border-radius: var(--radius-card);
        border-collapse: separate;
        border-spacing: 0;
        overflow: hidden;
        box-shadow: var(--shadow-card);
    }

    .responsive-table thead {
        display: table-header-group;
    }

    .responsive-table tbody {
        display: table-row-group;
    }

    .responsive-table tr {
        display: table-row;
        margin: 0;
        padding: 0;
        border: 0;
        border-radius: 0;
        box-shadow: none;
    }

    .responsive-table th,
    .responsive-table td {
        display: table-cell;
        padding: 14px 16px;
        border-bottom: 1px solid var(--color-border);
        text-align: left;
        vertical-align: middle;
    }

    .responsive-table th {
        color: var(--color-muted);
        font-size: 0.92rem;
        font-weight: 800;
        background: #f1f5f9;
    }

    .responsive-table td::before {
        content: none;
    }
}