:root {
    --bg-color: #f0f2f5;
    --surface-color: #ffffff;
    --text-color: #1f2933;
    --muted-text-color: #52606d;
    --border-color: #d9e2ec;
    --shadow-color: rgba(15, 23, 42, 0.12);
    --accent-color: #2563eb;
    --accent-contrast: #ffffff;
    --hover-color: #e9ecef;
    --table-header-color: #f9fafb;
    --row-hover-color: #f1f3f5;
}

html[data-theme="dark"] {
    --bg-color: #0f172a;
    --surface-color: #111827;
    --text-color: #e2e8f0;
    --muted-text-color: #94a3b8;
    --border-color: #1e293b;
    --shadow-color: rgba(15, 23, 42, 0.6);
    --accent-color: #38bdf8;
    --accent-contrast: #0f172a;
    --hover-color: #1f2937;
    --table-header-color: #0b1220;
    --row-hover-color: #182235;
}

body {
    font-family: 'Poppins', sans-serif;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.25s ease, color 0.25s ease;
}

header {
    background-color: var(--surface-color);
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 2px 12px var(--shadow-color);
    text-align: center;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    max-width: 1100px;
    margin: 0 auto;
}

.header-inner h1 {
    margin: 0;
    font-size: 1.6rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.theme-toggle {
    border: 1px solid var(--border-color);
    background-color: var(--surface-color);
    color: var(--text-color);
    padding: 8px 14px;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease;
}

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

.theme-toggle__label {
    font-weight: 600;
}

main {
    display: flex;
    padding: 20px;
    gap: 20px;
    max-width: 1100px;
    margin: 0 auto;
}

account-list, portfolio-details {
    background-color: var(--surface-color);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 12px var(--shadow-color);
    border: 1px solid var(--border-color);
}

account-list {
    flex: 1;
}

portfolio-details {
    flex: 3;
}

footer {
    text-align: center;
    padding: 20px;
    background-color: var(--surface-color);
    border-top: 1px solid var(--border-color);
    margin-top: 20px;
    color: var(--muted-text-color);
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th, td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background-color: var(--table-header-color);
}

account-list ul {
    list-style-type: none;
    padding: 0;
}

account-list li a {
    display: block;
    padding: 10px;
    text-decoration: none;
    color: var(--text-color);
    border-radius: 4px;
    transition: background-color 0.3s, box-shadow 0.3s;
}

account-list li a:hover {
    background-color: var(--hover-color);
    box-shadow: 0 1px 6px var(--shadow-color);
}

tr:hover {
    background-color: var(--row-hover-color);
}

@media (max-width: 900px) {
    main {
        flex-direction: column;
    }

    .header-inner {
        flex-direction: column;
    }
}