@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

:root {
    --bg: #f5f6fa;
    --surface: #ffffff;
    --surface-alt: #f0f2f7;
    --surface-hover: #fafbfd;
    --border: #e4e7ef;
    --border-focus: #4f46e5;
    --text: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --accent: #4f46e5;
    --accent-light: #eef2ff;
    --accent-hover: #4338ca;
    --accent-soft: rgba(79,70,229,.08);
    --green: #059669;
    --green-light: #ecfdf5;
    --green-soft: rgba(5,150,105,.08);
    --orange: #ea580c;
    --orange-light: #fff7ed;
    --red: #dc2626;
    --red-light: #fef2f2;
    --purple: #7c3aed;
    --purple-light: #f5f3ff;
    --blue: #2563eb;
    --blue-light: #eff6ff;
    --radius: 14px;
    --radius-sm: 10px;
    --shadow-xs: 0 1px 2px rgba(0,0,0,.04);
    --shadow: 0 1px 3px rgba(0,0,0,.06), 0 2px 8px rgba(0,0,0,.04);
    --shadow-md: 0 4px 12px rgba(0,0,0,.07);
    --shadow-lg: 0 8px 30px rgba(0,0,0,.1);
    --transition: .2s cubic-bezier(.4,0,.2,1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

/* ── Navbar ── */
.navbar {
    background: rgba(255,255,255,.85);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border-bottom: 1px solid var(--border);
    padding: 0 2rem;
    height: 64px;
    display: flex;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}
.navbar a { text-decoration: none; color: var(--text); }
.nav-brand {
    font-size: 1.25rem;
    font-weight: 800;
    letter-spacing: -.03em;
    display: flex;
    align-items: center;
    gap: .4rem;
}
.nav-brand .logo {
    width: 32px; height: 32px; border-radius: 8px;
    background: var(--accent);
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-size: .85rem; font-weight: 700;
}
.nav-brand span { color: var(--accent); }
.nav-links { margin-left: auto; display: flex; gap: .5rem; }
.nav-links a {
    font-size: .85rem;
    font-weight: 500;
    color: var(--text-secondary);
    padding: .45rem .85rem;
    border-radius: 8px;
    transition: all var(--transition);
}
.nav-links a:hover { background: var(--accent-soft); color: var(--accent); }
.nav-links a.active { background: var(--accent-light); color: var(--accent); font-weight: 600; }

/* ── Layout ── */
.container { max-width: 1160px; margin: 0 auto; padding: 2rem 1.5rem; }
.page-header { margin-bottom: 1.75rem; }
.page-header h1 { font-size: 1.65rem; font-weight: 700; letter-spacing: -.03em; }
.page-header p { color: var(--text-secondary); margin-top: .3rem; font-size: .9rem; }

/* ── Cards grid ── */
.calc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1rem;
}
.calc-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.35rem;
    text-decoration: none;
    color: var(--text);
    transition: all var(--transition);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}
.calc-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent 60%, var(--accent-soft));
    opacity: 0;
    transition: opacity var(--transition);
}
.calc-card:hover::before { opacity: 1; }
.calc-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--accent);
    transform: translateY(-3px);
}
.calc-card .icon {
    width: 42px; height: 42px;
    border-radius: var(--radius-sm);
    display: flex; align-items: center; justify-content: center;
    font-size: 1.2rem;
    margin-bottom: .65rem;
    position: relative;
}
.calc-card h3 { font-size: .95rem; font-weight: 600; margin-bottom: .3rem; position: relative; }
.calc-card p { font-size: .8rem; color: var(--text-secondary); flex: 1; position: relative; line-height: 1.5; }
.calc-card .arrow {
    margin-top: .85rem;
    font-size: .75rem;
    font-weight: 600;
    color: var(--accent);
    position: relative;
    display: flex;
    align-items: center;
    gap: .3rem;
}
.calc-card:hover .arrow { gap: .5rem; }

/* ── Calculator layout ── */
.calc-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    align-items: start;
}
@media (max-width: 800px) {
    .calc-layout { grid-template-columns: 1fr; }
    .field-row { grid-template-columns: 1fr !important; }
}

.calc-form, .calc-results {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-xs);
}
.calc-results { position: sticky; top: 80px; }
.calc-form h2, .calc-results h2 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1.15rem;
    padding-bottom: .65rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: .5rem;
}

/* ── Form fields ── */
.field { margin-bottom: 1rem; }
.field label {
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: .75rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: .05em;
    margin-bottom: .4rem;
}
.field label .field-value {
    font-size: .85rem;
    font-weight: 700;
    color: var(--accent);
    text-transform: none;
    letter-spacing: normal;
}
.input-wrap {
    position: relative;
    display: flex;
    align-items: center;
}
.input-wrap .prefix {
    position: absolute;
    left: .75rem;
    font-size: .85rem;
    font-weight: 600;
    color: var(--text-muted);
    pointer-events: none;
    z-index: 1;
}
.input-wrap .suffix {
    position: absolute;
    right: .75rem;
    font-size: .8rem;
    font-weight: 500;
    color: var(--text-muted);
    pointer-events: none;
}
.input-wrap input.has-prefix { padding-left: 1.8rem; }
.input-wrap input.has-suffix { padding-right: 2.5rem; }

.field input[type="number"], .field input[type="text"], .field select {
    width: 100%;
    padding: .55rem .75rem;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: .9rem;
    font-family: inherit;
    color: var(--text);
    background: var(--surface);
    transition: all var(--transition);
}
.field input:focus, .field select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-soft);
}
.field input:hover, .field select:hover { border-color: #c7c9d3; }

.field input[type="range"] {
    width: 100%;
    height: 6px;
    -webkit-appearance: none;
    appearance: none;
    background: var(--border);
    border-radius: 3px;
    outline: none;
    margin-top: .5rem;
    cursor: pointer;
}
.field input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px; height: 18px;
    border-radius: 50%;
    background: var(--accent);
    border: 3px solid #fff;
    box-shadow: 0 1px 4px rgba(0,0,0,.2);
    cursor: pointer;
    transition: transform .15s;
}
.field input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.15); }
.field input[type="range"]::-moz-range-thumb {
    width: 18px; height: 18px;
    border-radius: 50%;
    background: var(--accent);
    border: 3px solid #fff;
    box-shadow: 0 1px 4px rgba(0,0,0,.2);
    cursor: pointer;
}

.field .hint { font-size: .7rem; color: var(--text-muted); margin-top: .25rem; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: .85rem; }

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: .5rem;
    padding: .65rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: .9rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all var(--transition);
    width: 100%;
}
.btn:active { transform: scale(.97); }
.btn-primary {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 2px 8px rgba(79,70,229,.25);
}
.btn-primary:hover {
    background: var(--accent-hover);
    box-shadow: 0 4px 16px rgba(79,70,229,.3);
    transform: translateY(-1px);
}

/* ── Results ── */
.result-hero {
    text-align: center;
    padding: 1.25rem;
    background: linear-gradient(135deg, var(--accent-light), #e0e7ff);
    border-radius: var(--radius-sm);
    margin-bottom: 1rem;
}
.result-hero .label {
    font-size: .7rem;
    font-weight: 700;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: .06em;
}
.result-hero .value {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--accent);
    margin-top: .1rem;
    letter-spacing: -.02em;
}
.result-hero .sub {
    font-size: .75rem;
    color: var(--text-secondary);
    margin-top: .25rem;
}

.result-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: .6rem;
    margin-bottom: 1rem;
}
.stat-card {
    padding: .75rem;
    background: var(--surface-alt);
    border-radius: 8px;
    text-align: center;
    border: 1px solid transparent;
    transition: all var(--transition);
}
.stat-card:hover { border-color: var(--border); }
.stat-card .label {
    font-size: .65rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: .04em;
}
.stat-card .value { font-size: 1.05rem; font-weight: 700; margin-top: .1rem; }
.stat-card.green { background: var(--green-light); }
.stat-card.green .value { color: var(--green); }
.stat-card.orange .value { color: var(--orange); }
.stat-card.purple { background: var(--purple-light); }
.stat-card.purple .value { color: var(--purple); }
.stat-card.blue { background: var(--blue-light); }
.stat-card.blue .value { color: var(--blue); }
.stat-card.red { background: var(--red-light); }
.stat-card.red .value { color: var(--red); }

/* ── Inflation toggle ── */
.inflation-toggle {
    display: flex;
    align-items: center;
    gap: .6rem;
    padding: .6rem .85rem;
    background: var(--surface-alt);
    border-radius: 8px;
    margin-bottom: 1rem;
    font-size: .8rem;
    font-weight: 500;
    color: var(--text-secondary);
    border: 1px solid var(--border);
}
.inflation-toggle .switch {
    position: relative;
    width: 36px; height: 20px;
    flex-shrink: 0;
}
.inflation-toggle .switch input { opacity: 0; width: 0; height: 0; }
.inflation-toggle .switch .slider {
    position: absolute;
    inset: 0;
    background: var(--border);
    border-radius: 10px;
    cursor: pointer;
    transition: all var(--transition);
}
.inflation-toggle .switch .slider::before {
    content: '';
    position: absolute;
    width: 16px; height: 16px;
    left: 2px; bottom: 2px;
    background: #fff;
    border-radius: 50%;
    transition: transform var(--transition);
    box-shadow: 0 1px 3px rgba(0,0,0,.15);
}
.inflation-toggle .switch input:checked + .slider { background: var(--accent); }
.inflation-toggle .switch input:checked + .slider::before { transform: translateX(16px); }
.inflation-toggle .inf-label { flex: 1; }
.inflation-toggle .inf-rate {
    font-weight: 700;
    color: var(--accent);
    font-size: .85rem;
}
.inflation-field {
    margin-top: .4rem;
    display: none;
}
.inflation-field.visible { display: block; }
.inflation-field input {
    width: 70px;
    padding: .3rem .5rem;
    border: 1.5px solid var(--border);
    border-radius: 6px;
    font-size: .8rem;
    font-family: inherit;
    text-align: center;
}
.inflation-field input:focus {
    outline: none;
    border-color: var(--accent);
}

/* ── Chart ── */
.chart-container {
    width: 100%;
    max-width: 200px;
    margin: 0 auto 1rem;
}
.chart-container canvas { width: 100% !important; height: auto !important; }

/* ── Breakdown table ── */
.breakdown { margin-top: .75rem; }
.breakdown summary {
    cursor: pointer;
    font-size: .8rem;
    font-weight: 600;
    color: var(--accent);
    padding: .5rem 0;
    display: flex;
    align-items: center;
    gap: .3rem;
    transition: color var(--transition);
}
.breakdown summary:hover { color: var(--accent-hover); }
.breakdown table {
    width: 100%;
    border-collapse: collapse;
    font-size: .75rem;
    margin-top: .5rem;
}
.breakdown th, .breakdown td {
    padding: .45rem .5rem;
    text-align: right;
    border-bottom: 1px solid var(--border);
}
.breakdown th {
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    font-size: .65rem;
    letter-spacing: .04em;
    position: sticky;
    top: 0;
    background: var(--surface);
}
.breakdown th:first-child, .breakdown td:first-child { text-align: left; }
.breakdown tbody tr:hover { background: var(--surface-alt); }

/* ── Toggle group ── */
.toggle-group {
    display: flex;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    background: var(--surface-alt);
    padding: 2px;
    gap: 2px;
}
.toggle-group label {
    flex: 1;
    text-align: center;
    padding: .45rem .6rem;
    font-size: .8rem;
    font-weight: 500;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all var(--transition);
    text-transform: none;
    letter-spacing: normal;
    border-radius: 6px;
}
.toggle-group input { display: none; }
.toggle-group input:checked + label {
    background: var(--accent);
    color: #fff;
    box-shadow: var(--shadow-xs);
}

/* ── Placeholder ── */
.results-placeholder {
    text-align: center;
    padding: 2.5rem 1rem;
    color: var(--text-muted);
}
.results-placeholder .icon { font-size: 2rem; margin-bottom: .5rem; opacity: .3; }
.results-placeholder p { font-size: .85rem; }

/* ── Breadcrumb ── */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: .35rem;
    font-size: .8rem;
    margin-bottom: .85rem;
}
.breadcrumb a { color: var(--text-muted); text-decoration: none; transition: color var(--transition); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { color: var(--border); font-size: .7rem; }
.breadcrumb .current { color: var(--text-secondary); font-weight: 500; }

/* ── Category header ── */
.category-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.75rem;
}
.category-icon {
    width: 52px; height: 52px;
    border-radius: var(--radius-sm);
    display: flex; align-items: center; justify-content: center;
    font-size: 1.5rem;
}

/* ── Section headers on index ── */
.section-label {
    font-size: .7rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: .06em;
    margin-bottom: .75rem;
    margin-top: 1.5rem;
}
.section-label:first-of-type { margin-top: 0; }

/* ── Info box ── */
.info-box {
    background: var(--surface-alt);
    border-radius: 8px;
    padding: .85rem 1rem;
    font-size: .8rem;
    color: var(--text-secondary);
    line-height: 1.65;
    border-left: 3px solid var(--accent);
}
.info-box strong { color: var(--text); }

/* ── Footer ── */
.footer {
    text-align: center;
    padding: 1.75rem;
    font-size: .75rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border);
    margin-top: 3rem;
}

/* ── Segment tabs ── */
.seg-tabs {
    display: flex;
    gap: 2px;
    background: var(--surface-alt);
    border: 1.5px solid var(--border);
    border-radius: 10px;
    padding: 3px;
    margin-bottom: 1.5rem;
    width: fit-content;
}
.seg-tab {
    padding: .45rem 1.4rem;
    border-radius: 7px;
    font-size: .875rem;
    font-weight: 600;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all var(--transition);
    user-select: none;
}
.seg-tab:hover { color: var(--text); }
.seg-tab.active {
    background: var(--surface);
    color: var(--accent);
    box-shadow: var(--shadow-xs);
}

/* ── Tab panes ── */
.calc-pane { display: none; }
.calc-pane.active { display: block; animation: fadeUp .25s ease both; }

/* ── Derived card extras ── */
.derived-uses {
    font-size: .7rem;
    color: var(--text-muted);
    margin-top: .4rem;
    display: flex;
    align-items: center;
    gap: .3rem;
    flex-wrap: wrap;
}
.derived-uses .uses-label { font-weight: 600; color: var(--text-secondary); }
.derived-uses .uses-chip {
    background: var(--accent-soft);
    color: var(--accent);
    padding: .1rem .45rem;
    border-radius: 4px;
    font-size: .68rem;
    font-weight: 600;
}

/* ── Prerequisite hint banners ── */
.prereq-hint {
    background: #fff7ed;
    border: 1px solid #fed7aa;
    border-radius: 8px;
    padding: .65rem .9rem;
    font-size: .8rem;
    color: #c2410c;
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    gap: .5rem;
    line-height: 1.5;
}
.prereq-hint a { color: #c2410c; font-weight: 600; text-decoration: underline; text-underline-offset: 2px; }
.prefill-notice {
    background: var(--green-light);
    border: 1px solid #6ee7b7;
    border-radius: 8px;
    padding: .65rem .9rem;
    font-size: .8rem;
    color: var(--green);
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    gap: .5rem;
    line-height: 1.5;
}

/* ── Readiness score bar ── */
.readiness-bar-wrap {
    background: var(--surface-alt);
    border-radius: 999px;
    height: 12px;
    overflow: hidden;
    margin: .5rem 0 .25rem;
}
.readiness-bar {
    height: 100%;
    border-radius: 999px;
    transition: width .6s cubic-bezier(.4,0,.2,1);
}

/* ── Animations ── */
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}
.calc-card { animation: fadeUp .35s ease both; }
.calc-card:nth-child(2) { animation-delay: .05s; }
.calc-card:nth-child(3) { animation-delay: .1s; }
.calc-card:nth-child(4) { animation-delay: .15s; }
.calc-card:nth-child(5) { animation-delay: .2s; }
.calc-card:nth-child(6) { animation-delay: .25s; }
.calc-card:nth-child(7) { animation-delay: .3s; }
.calc-card:nth-child(8) { animation-delay: .35s; }
.calc-card:nth-child(9) { animation-delay: .4s; }
.calc-card:nth-child(10) { animation-delay: .45s; }

#results { animation: fadeUp .3s ease; }