/* ── Design tokens ─────────────────────────────────── */
:root {
    --ground:   #0A1220;
    --surface:  rgba(255,255,255,0.045);
    --surface-b:rgba(255,255,255,0.09);
    --text:     #E8ECF4;
    --text-dim: rgba(232,236,244,0.42);
    --accent:   #3B82F6;
    --accent-g: rgba(59,130,246,0.22);
    --radius:   18px;
}

[data-theme="light"] {
    --ground:   #EFF6FF;
    --surface:  rgba(255,255,255,0.82);
    --surface-b:rgba(0,0,0,0.07);
    --text:     #0A1A2E;
    --text-dim: rgba(10,26,46,0.42);
    --accent:   #2563EB;
    --accent-g: rgba(37,99,235,0.14);
}

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

/* ── Base ──────────────────────────────────────────── */
body {
    font-family: -apple-system, "Apple SD Gothic Neo", "Malgun Gothic",
                 "Nanum Gothic", "NanumGothic", sans-serif;
    background: var(--ground);
    color: var(--text);
    min-height: 100vh;
    transition: background 0.4s, color 0.3s;
    overflow-x: hidden;
}

/* ── Layout ────────────────────────────────────────── */
.layout {
    position: relative;
    z-index: 1;
    max-width: 680px;
    margin: 0 auto;
    padding: 0 24px 72px;
}

/* ── Header ────────────────────────────────────────── */
header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 28px 0 0;
}

.brand { display: flex; align-items: center; gap: 11px; }

.brand-mark {
    width: 36px;
    height: 36px;
    border-radius: 10px;
    background: var(--accent);
    color: #fff;
    font-size: 19px;
    font-weight: 900;
    display: flex;
    align-items: center;
    justify-content: center;
}

.brand-name {
    font-size: 14px;
    font-weight: 800;
    letter-spacing: 0.1em;
    color: var(--text);
}
.brand-name span { color: var(--accent); }

#theme-toggle {
    background: var(--surface);
    border: 1px solid var(--surface-b);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text);
    transition: background 0.25s, border-color 0.25s;
}
#theme-toggle:hover { background: var(--surface-b); }
#theme-toggle svg { width: 17px; height: 17px; }

[data-theme="dark"]  .icon-sun  { display: none; }
[data-theme="light"] .icon-moon { display: none; }

/* ── Main Nav ──────────────────────────────────────── */
.main-nav {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    justify-content: center;
    padding: 14px 0;
    border-bottom: 1px solid var(--surface-b);
    margin-bottom: 8px;
}
.main-nav a {
    padding: 7px 14px;
    border-radius: 50px;
    font-size: 12px;
    font-weight: 700;
    text-decoration: none;
    color: var(--text-dim);
    background: var(--surface);
    border: 1.5px solid var(--surface-b);
    transition: all 0.2s;
}
.main-nav a:hover,
.main-nav a.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

/* ── Hero ──────────────────────────────────────────── */
.hero {
    padding: 60px 0 52px;
    text-align: center;
}

.eyebrow {
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 22px;
}

h1 {
    font-size: clamp(36px, 9vw, 54px);
    font-weight: 900;
    line-height: 1.12;
    letter-spacing: -0.025em;
    color: var(--text);
    margin-bottom: 16px;
}
h1 em {
    font-style: normal;
    color: var(--accent);
}

.hero-sub {
    font-size: 14px;
    color: var(--text-dim);
    letter-spacing: 0.03em;
}

/* ── Salary Tool ───────────────────────────────────── */
.salary-tool {
    margin-top: 40px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Toggle group */
.toggle-group {
    display: flex;
    gap: 8px;
    justify-content: center;
}

.toggle-btn {
    padding: 10px 28px;
    border-radius: 50px;
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    border: 1.5px solid var(--surface-b);
    background: var(--surface);
    color: var(--text-dim);
    transition: all 0.2s;
    font-family: inherit;
}
.toggle-btn:hover {
    background: var(--surface-b);
    color: var(--text);
}
.toggle-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
    box-shadow: 0 0 20px var(--accent-g);
}

/* Input group */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
    background: var(--surface);
    border: 1.5px solid var(--surface-b);
    border-radius: var(--radius);
    padding: 24px;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
}

.input-group label {
    font-size: 13px;
    font-weight: 700;
    color: var(--text-dim);
    letter-spacing: 0.04em;
}

.input-row {
    display: flex;
    align-items: center;
    gap: 10px;
}

.input-row input[type="number"] {
    flex: 1;
    padding: 14px 18px;
    border-radius: 12px;
    border: 1.5px solid var(--surface-b);
    background: var(--surface-b);
    color: var(--text);
    font-size: 22px;
    font-weight: 800;
    font-family: inherit;
    outline: none;
    transition: border-color 0.2s, background 0.2s;
    -moz-appearance: textfield;
}
.input-row input[type="number"]::-webkit-inner-spin-button,
.input-row input[type="number"]::-webkit-outer-spin-button { -webkit-appearance: none; }
.input-row input[type="number"]:focus {
    border-color: var(--accent);
    background: rgba(59,130,246,0.06);
}
.input-row input[type="number"]::placeholder { color: var(--text-dim); font-size: 18px; font-weight: 400; }

.input-unit {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-dim);
    white-space: nowrap;
}

#calc-btn {
    width: 100%;
    padding: 16px;
    border-radius: 12px;
    border: none;
    background: var(--accent);
    color: #fff;
    font-size: 16px;
    font-weight: 800;
    letter-spacing: 0.04em;
    cursor: pointer;
    font-family: inherit;
    box-shadow: 0 0 32px var(--accent-g), 0 4px 16px rgba(0,0,0,0.2);
    transition: transform 0.15s, box-shadow 0.2s, background 0.2s;
}
#calc-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 48px var(--accent-g), 0 8px 24px rgba(0,0,0,0.25);
}
#calc-btn:active { transform: scale(0.98); }

/* Result area */
#result-area {
    display: flex;
    flex-direction: column;
    gap: 14px;
    animation: slideUp 0.35s ease forwards;
}

.result-card {
    border: 1.5px solid var(--accent);
    border-radius: var(--radius);
    padding: 28px;
    background: var(--surface);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    box-shadow: 0 0 40px var(--accent-g);
}

.result-title {
    font-size: 16px;
    font-weight: 800;
    color: var(--text);
    margin-bottom: 18px;
    letter-spacing: -0.01em;
}

.table-wrap { overflow-x: auto; margin-bottom: 0; }

.breakdown-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
    min-width: 300px;
}

.breakdown-table th,
.breakdown-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--surface-b);
    line-height: 1.5;
}

.breakdown-table thead th {
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-dim);
    background: var(--surface);
    white-space: nowrap;
}

.breakdown-table tbody td { color: var(--text-dim); }
.breakdown-table tbody td:first-child { color: var(--text); font-weight: 600; }
.breakdown-table tbody td:nth-child(2) { font-weight: 700; text-align: right; font-variant-numeric: tabular-nums; }
.breakdown-table tbody td:nth-child(3) { font-size: 12px; text-align: right; color: var(--text-dim); }
.breakdown-table tbody tr:hover { background: var(--surface-b); }

.highlight-row td {
    color: var(--accent) !important;
    font-weight: 800 !important;
    font-size: 16px;
    border-top: 2px solid var(--accent);
    border-bottom: none;
}

/* Annual section */
.annual-section {
    margin-top: 20px;
    padding-top: 16px;
    border-top: 2px solid var(--surface-b);
}

.annual-summary {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid var(--surface-b);
}
.annual-summary:last-child { border-bottom: none; }

.annual-label {
    font-size: 14px;
    color: var(--text-dim);
}

.annual-value {
    font-size: 16px;
    font-weight: 800;
    color: var(--text);
}

.annual-value.deduct {
    color: var(--text-dim);
    font-size: 14px;
    font-weight: 700;
}

/* Reset button */
#reset-btn {
    align-self: center;
    padding: 11px 28px;
    border-radius: 50px;
    border: 1.5px solid var(--surface-b);
    background: var(--surface);
    color: var(--text-dim);
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    font-family: inherit;
    transition: all 0.2s;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}
#reset-btn:hover {
    background: var(--surface-b);
    color: var(--text);
    border-color: var(--accent);
}

/* ── Guide content ─────────────────────────────────── */
.guide-section {
    margin-top: 72px;
    padding-top: 56px;
    border-top: 1px solid var(--surface-b);
}

.guide-article {
    margin-bottom: 56px;
}

.guide-article h2 {
    font-size: 22px;
    font-weight: 900;
    color: var(--text);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--accent);
    letter-spacing: -0.01em;
}

.guide-article h3 {
    font-size: 16px;
    font-weight: 800;
    color: var(--text);
    margin: 28px 0 10px;
}

.guide-article p {
    font-size: 14px;
    line-height: 1.9;
    color: var(--text-dim);
    margin-bottom: 14px;
}

.guide-article ul,
.guide-article ol {
    font-size: 14px;
    line-height: 1.85;
    color: var(--text-dim);
    padding-left: 20px;
    margin-bottom: 16px;
}

.guide-article li { margin-bottom: 8px; }

.guide-article strong { color: var(--text); font-weight: 700; }

.guide-article code {
    background: var(--surface-b);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 13px;
    font-family: monospace;
}

/* Info table (tax brackets, etc.) */
.info-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
    min-width: 400px;
}

.info-table th,
.info-table td {
    padding: 10px 14px;
    border: 1px solid var(--surface-b);
    text-align: left;
    line-height: 1.5;
}

.info-table th {
    background: var(--surface);
    font-weight: 700;
    color: var(--text);
    white-space: nowrap;
}

.info-table td { color: var(--text-dim); }
.info-table tbody tr:hover { background: var(--surface); }

/* FAQ */
.faq-section { margin-top: 48px; }

.faq-section h2 {
    font-size: 22px;
    font-weight: 900;
    color: var(--text);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--accent);
}

.faq-item {
    border: 1px solid var(--surface-b);
    border-radius: 14px;
    padding: 20px 24px;
    margin-bottom: 12px;
    background: var(--surface);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.faq-item h3 {
    font-size: 14px;
    font-weight: 800;
    color: var(--text);
    margin-bottom: 10px;
    line-height: 1.5;
}

.faq-item p {
    font-size: 14px;
    line-height: 1.8;
    color: var(--text-dim);
    margin: 0;
}

/* ── Footer ────────────────────────────────────────── */
footer {
    text-align: center;
    padding-top: 52px;
    font-size: 12px;
    color: var(--text-dim);
    letter-spacing: 0.03em;
}

.footer-link {
    color: var(--accent);
    text-decoration: none;
    font-weight: 700;
}
.footer-link:hover { text-decoration: underline; }

/* ── Animations ────────────────────────────────────── */
@keyframes slideUp {
    from { opacity: 0; transform: translateY(16px); }
    to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* ── Responsive ────────────────────────────────────── */
@media (max-width: 480px) {
    .toggle-btn { padding: 9px 18px; font-size: 13px; }
    .input-group { padding: 18px; }
    .input-row input[type="number"] { font-size: 18px; padding: 12px 14px; }
    .result-card { padding: 20px 16px; }
    .breakdown-table th,
    .breakdown-table td { padding: 10px 10px; font-size: 13px; }
    .highlight-row td { font-size: 14px; }
    .annual-value { font-size: 14px; }
    h1 { font-size: clamp(30px, 8vw, 44px); }
}

/* ── Reduced motion ────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
    #result-area,
    .round-row,
    .legend {
        animation: none;
    }
    #result-area { opacity: 1; transform: none; }
    #calc-btn { transition: none; }
    body { transition: none; }
}