/* ===================================================================
   Stock Purification Calculator — Tool ID 16
   Scoped under .pur-section. Reuses design-system tokens (tokens.css)
   with literal fallbacks. RTL-first, zero inline styles.
   =================================================================== */

.pur-section {
    --pur-navy:        var(--navy, #152D50);
    --pur-navy-2:      var(--navy-light, #1A3456);
    --pur-teal:        var(--teal, #0E7C7B);
    --pur-teal-bg:     var(--teal-bg, #EBF7F7);
    --pur-gold:        var(--gold, #C08A2E);
    --pur-gold-bg:     var(--gold-bg, #FAF3E5);
    --pur-surface:     #ffffff;
    --pur-bg:          var(--surface-2, #f5f7fa);
    --pur-border:      var(--border, #DDE5EF);
    --pur-border-soft: var(--border-soft, #E8EFF8);
    --pur-text-1:      var(--navy, #152D50);
    --pur-text-2:      #3a4a5e;
    --pur-text-3:      #5d6a7e; /* WCAG AA: 5.4:1 on #fff (was #6b7a90 = 4.38:1) */
    --pur-danger:      var(--danger, #b91c1c);
    --pur-radius:      var(--radius-lg, 14px);
    --pur-radius-sm:   var(--radius-md, 8px);
    --pur-shadow:      var(--shadow-md, 0 2px 16px rgba(21, 45, 80, .08));
    display: block;
    color: var(--pur-text-1);
    font-size: 15px;
}
.pur-section * { box-sizing: border-box; }

/* ── HERO ── */
.pur-hero {
    background: linear-gradient(135deg, var(--pur-navy) 0%, var(--pur-navy-2) 100%);
    border-radius: var(--pur-radius);
    padding: 40px 24px;
    text-align: center;
    margin-block: 8px 24px;
}
.pur-hero h1 { color: #fff; font-size: clamp(22px, 4vw, 32px); font-weight: 800; margin-block-end: 10px; }
.pur-hero-desc { color: rgba(255, 255, 255, .82); font-size: 15px; max-width: 600px; margin: 0 auto 24px; line-height: 1.7; }
.pur-hero-badge {
    display: inline-flex; align-items: center; gap: 6px;
    background: rgba(201, 168, 76, .18); border: 1px solid rgba(201, 168, 76, .4);
    color: #E5C77A; border-radius: 20px; padding: 5px 14px; font-size: 12.5px; margin-block-end: 16px;
}
.pur-hero-stats { display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }
.pur-hero-stat {
    background: rgba(255, 255, 255, .08); border: 1px solid rgba(255, 255, 255, .14);
    border-radius: var(--pur-radius-sm); padding: 10px 20px; text-align: center;
}
.pur-hero-stat strong { display: block; color: #E5C77A; font-size: 16px; font-weight: 800; }
.pur-hero-stat span { color: rgba(255, 255, 255, .7); font-size: 11.5px; }

/* ── LAYOUT ── */
.pur-main { padding-block-end: 32px; }
.pur-grid { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 24px; align-items: start; }
.pur-form-col, .pur-result-col { min-width: 0; }
@media (max-width: 900px) {
    .pur-grid { grid-template-columns: minmax(0, 1fr); }
    .pur-result-col { order: -1; }
}

/* ── INFO BOX ── */
.pur-info-box {
    background: var(--pur-gold-bg); border: 1px solid var(--border-gold, rgba(201, 168, 76, .3));
    border-radius: var(--pur-radius-sm); padding: 14px 18px; font-size: 13.5px;
    color: #5a4020; line-height: 1.7; margin-block-end: 22px;
}
.pur-info-box strong { display: block; margin-block-end: 4px; color: #3d2a10; }
.pur-info-box p { margin: 0; }

/* ── CARDS ── */
.pur-card {
    background: var(--pur-surface); border-radius: var(--pur-radius);
    box-shadow: var(--pur-shadow); border: 1px solid var(--pur-border-soft); margin-block-end: 20px;
}
.pur-card-head { padding: 18px 22px 14px; border-block-end: 1px solid var(--pur-border-soft); display: flex; align-items: center; gap: 10px; }
.pur-card-icon {
    width: 38px; height: 38px; border-radius: 10px; background: var(--pur-teal-bg); color: var(--pur-teal);
    display: flex; align-items: center; justify-content: center; font-size: 18px; flex-shrink: 0;
}
.pur-card-title { font-size: 15px; font-weight: 700; color: var(--pur-text-1); margin: 0; }
.pur-card-sub { font-size: 12px; color: var(--pur-text-3); margin: 2px 0 0; }
.pur-card-body { padding: 20px 22px; }

/* ── TABS ── */
.pur-tabs { display: flex; gap: 8px; margin-block-end: 18px; border: 1.5px solid var(--pur-border); border-radius: var(--pur-radius-sm); padding: 4px; background: var(--pur-bg); }
.pur-tab {
    flex: 1; padding: 10px; min-height: 42px; border: none; border-radius: 6px; background: transparent;
    font-family: inherit; font-size: 13.5px; font-weight: 700; color: var(--pur-text-3); cursor: pointer; transition: all .15s;
}
.pur-tab.active { background: var(--pur-surface); color: var(--pur-teal); box-shadow: var(--shadow-sm, 0 1px 4px rgba(21, 45, 80, .08)); }

/* ── FIELDS ── */
.pur-field { margin-block-end: 18px; }
.pur-field:last-child { margin-block-end: 0; }
.pur-field > label { display: block; font-size: 13px; font-weight: 700; color: var(--pur-text-2); margin-block-end: 7px; }
.pur-hint { font-weight: 400; color: var(--pur-text-3); font-size: 11.5px; margin-inline-start: 6px; }
.pur-input-wrap { position: relative; }
.pur-input-wrap input {
    width: 100%; border: 1.5px solid var(--pur-border); border-radius: var(--pur-radius-sm);
    padding-block: 11px; padding-inline: 14px 48px; font-family: inherit; font-size: 15px;
    color: var(--pur-text-1); background: #fff; transition: border-color .15s, box-shadow .15s; appearance: none;
}
.pur-input-wrap input:focus { outline: none; border-color: var(--pur-teal); box-shadow: 0 0 0 3px rgba(14, 124, 123, .12); }
.pur-input-unit { position: absolute; top: 50%; inset-inline-end: 14px; transform: translateY(-50%); font-size: 12px; color: var(--pur-text-3); pointer-events: none; font-weight: 700; }

/* ── CHIPS ── */
.pur-chip-group { display: flex; flex-wrap: wrap; gap: 8px; margin-block-end: 10px; }
.pur-chip {
    padding: 8px 18px; min-height: 40px; border-radius: 20px; border: 1.5px solid var(--pur-border);
    background: var(--pur-bg); cursor: pointer; font-family: inherit; font-size: 13px; color: var(--pur-text-2); transition: all .15s; user-select: none;
}
.pur-chip:hover { border-color: var(--pur-teal); color: var(--pur-teal); background: var(--pur-teal-bg); }
.pur-chip.active { border-color: var(--pur-teal); background: var(--pur-teal-bg); color: var(--pur-teal); font-weight: 700; }

/* ── BUTTONS ── */
.pur-btn-calc {
    width: 100%; padding: 14px; background: var(--pur-teal); color: #fff; border: none;
    border-radius: var(--pur-radius-sm); font-family: inherit; font-size: 15px; font-weight: 700; cursor: pointer;
    transition: background .15s; display: flex; align-items: center; justify-content: center; gap: 8px; margin-block-start: 4px;
}
.pur-btn-calc:hover { background: #0a6362; }
.pur-btn-reset {
    width: 100%; padding: 11px; background: transparent; color: var(--pur-text-3); border: 1.5px solid var(--pur-border);
    border-radius: var(--pur-radius-sm); font-family: inherit; font-size: 13px; cursor: pointer; margin-block-start: 8px; transition: all .15s;
}
.pur-btn-reset:hover { border-color: var(--pur-danger); color: var(--pur-danger); }

/* ── FORMULA ── */
.pur-formula-section { margin-block-end: 24px; }
.pur-section-title {
    font-size: 17px; font-weight: 800; color: var(--pur-text-1); margin-block-end: 16px;
    padding-block-end: 10px; border-block-end: 2px solid var(--pur-border); display: flex; align-items: center; gap: 8px;
}
.pur-formula-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 560px) { .pur-formula-grid { grid-template-columns: 1fr; } }
.pur-formula-card { background: var(--pur-surface); border: 1.5px solid var(--pur-border); border-radius: var(--pur-radius-sm); padding: 14px 16px; }
.pur-fc-label { font-size: 11.5px; color: var(--pur-text-3); margin-block-end: 6px; font-weight: 700; letter-spacing: .3px; }
.pur-fc-formula { font-size: 12.5px; color: var(--pur-text-1); background: var(--pur-bg); border-radius: 6px; padding: 8px 12px; font-family: 'Courier New', monospace; text-align: left; }
.pur-formula-note { font-size: 12px; color: var(--pur-text-3); margin-block-start: 12px; line-height: 1.7; }

/* ── DISTINCTION ── */
.pur-distinction { background: var(--pur-surface); border: 1.5px solid var(--pur-border); border-radius: var(--pur-radius); overflow: hidden; margin-block-end: 24px; }
.pur-db-head { background: linear-gradient(135deg, var(--pur-navy-2), var(--pur-navy)); color: #fff; padding: 15px 20px; font-size: 15px; font-weight: 800; display: flex; align-items: center; gap: 8px; }
.pur-db-body { display: grid; grid-template-columns: 1fr 1fr; }
@media (max-width: 560px) { .pur-db-body { grid-template-columns: 1fr; } }
.pur-db-col { padding: 18px 20px; }
.pur-db-col:first-child { border-inline-end: 1px solid var(--pur-border); }
.pur-db-col-title { font-size: 13px; font-weight: 700; margin-block-end: 12px; }
.pur-db-col-title.tat { color: var(--pur-teal); }
.pur-db-col-title.zak { color: var(--pur-gold); }
.pur-db-list { list-style: none; margin: 0; padding: 0; }
.pur-db-list li { font-size: 13px; color: var(--pur-text-2); padding-block: 5px; display: flex; align-items: flex-start; gap: 8px; }
.pur-db-list.tat li::before { content: '✓'; color: var(--pur-teal); font-weight: 800; flex-shrink: 0; }
.pur-db-list.zak li::before { content: '★'; color: var(--pur-gold); font-weight: 800; flex-shrink: 0; }

/* ── FAQ ── */
.pur-faq-section { margin-block-end: 8px; }
.pur-faq-item { border: 1px solid var(--pur-border); border-radius: var(--pur-radius-sm); margin-block-end: 8px; overflow: hidden; }
.pur-faq-q {
    width: 100%; padding: 14px 18px; font-size: 14px; font-weight: 700; cursor: pointer; display: flex;
    justify-content: space-between; align-items: center; gap: 12px; background: var(--pur-surface); border: none; font-family: inherit; color: var(--pur-text-1); text-align: start;
}
.pur-faq-q:hover { background: var(--pur-bg); }
.pur-faq-arrow { transition: transform .2s; color: var(--pur-text-3); font-size: 11px; flex-shrink: 0; }
.pur-faq-a { padding-inline: 18px; max-height: 0; overflow: hidden; transition: max-height .25s, padding .25s; background: var(--pur-bg); font-size: 13.5px; color: var(--pur-text-2); line-height: 1.75; }
.pur-faq-item.open .pur-faq-arrow { transform: rotate(180deg); }
.pur-faq-item.open .pur-faq-a { max-height: 420px; padding-block: 14px; }

/* ── RESULT SIDEBAR ── */
.pur-result-card { position: sticky; top: 20px; }
.pur-result-head { padding: 18px 22px 14px; border-block-end: 1px solid var(--pur-border-soft); display: flex; align-items: center; gap: 10px; }
.pur-result-icon { font-size: 22px; }
.pur-result-title { font-size: 15px; font-weight: 800; color: var(--pur-text-1); margin: 0; }
.pur-result-body { padding: 20px 22px; }
.pur-result-empty { text-align: center; padding: 28px 0; color: var(--pur-text-3); font-size: 13.5px; line-height: 1.8; }
.pur-result-empty.hidden { display: none; }
.pur-re-icon { font-size: 40px; margin-block-end: 10px; }
.pur-result-data { display: none; }
.pur-result-data.show { display: block; }

.pur-amount-box { background: linear-gradient(135deg, var(--pur-navy) 0%, var(--pur-navy-2) 100%); border-radius: var(--pur-radius); padding: 20px; margin-block-end: 16px; text-align: center; }
.pur-amount-label { color: rgba(255, 255, 255, .65); font-size: 12px; margin-block-end: 6px; }
.pur-amount-value { color: #fff; font-size: 28px; font-weight: 800; letter-spacing: -.5px; }
.pur-amount-note { color: #E5C77A; font-size: 12px; margin-block-start: 4px; }

.pur-rb-row { display: flex; justify-content: space-between; align-items: center; padding-block: 10px; border-block-end: 1px solid var(--pur-border-soft); font-size: 13.5px; }
.pur-rb-row:last-child { border-block-end: none; }
.pur-rb-label { color: var(--pur-text-3); }
.pur-rb-label.pur-strong { font-weight: 700; color: var(--pur-text-2); }
.pur-rb-value { font-weight: 700; color: var(--pur-text-1); }
.pur-rb-value.accent { color: var(--pur-teal); }
.pur-rb-value.total { color: var(--pur-navy); font-size: 15px; }

.pur-reminder { background: var(--pur-gold-bg); border: 1px solid var(--border-gold, rgba(201, 168, 76, .3)); border-radius: 8px; padding: 10px 14px; margin-block-start: 12px; font-size: 12.5px; color: #5a4020; text-align: center; line-height: 1.6; }
.pur-disclaimer { background: var(--pur-bg); border: 1px solid var(--pur-border-soft); border-radius: var(--pur-radius-sm); padding: 12px 16px; font-size: 12px; color: var(--pur-text-3); line-height: 1.7; }
.pur-disclaimer strong { color: var(--pur-text-2); }

/* a11y: visible keyboard focus ring (WCAG 2.4.7) — guards against any global outline reset */
.pur-section button:focus-visible,
.pur-section a:focus-visible,
.pur-section input:focus-visible { outline: 2px solid var(--pur-teal); outline-offset: 2px; }

/* ── INTERNAL-LINK CTA CARD ── */
.pur-links-card { background: var(--pur-surface); border: 1.5px solid var(--pur-border); border-radius: var(--pur-radius); overflow: hidden; margin-block-end: 24px; }
.pur-links-head { background: linear-gradient(135deg, var(--pur-navy-2), var(--pur-navy)); color: #fff; padding: 14px 20px; font-size: 14.5px; font-weight: 800; }
.pur-links-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--pur-border-soft); }
@media (max-width: 480px) { .pur-links-grid { grid-template-columns: 1fr; } }
.pur-link-item { background: var(--pur-surface); padding: 14px 18px; font-size: 13.5px; font-weight: 700; color: var(--pur-teal); text-decoration: none; transition: background .15s; display: block; }
.pur-link-item:hover { background: var(--pur-teal-bg); }