/* =============================================================
   ND Filter Calculator – style.css
   Based on JY Tools shared design system (Inter font, #7c3aed theme)
   ============================================================= */

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

:root {
    --color-primary: #7c3aed;
    --color-primary-light: #a78bfa;
    --color-primary-dark: #5b21b6;
    --color-bg: #f8f7ff;
    --color-surface: #ffffff;
    --color-border: #e5e7eb;
    --color-text: #1f2937;
    --color-text-muted: #6b7280;
    --color-badge-od: #7c3aed;
    --color-badge-stack: #059669;
    --color-badge-laser: #dc2626;
    --radius: 10px;
    --shadow: 0 2px 8px rgba(0,0,0,0.07);
    --shadow-md: 0 4px 16px rgba(124,58,237,0.10);
    --transition: 0.18s ease;
}

html { font-size: 16px; }

body {
    font-family: 'Inter', system-ui, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
}

/* ── Container ── */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.25rem 2rem;
}

/* ── Header ── */
header {
    padding: 1.5rem 0 1rem;
    text-align: left;
}

.header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.75rem;
}

header h1 {
    font-size: clamp(1.4rem, 3vw, 2rem);
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
}

.subtitle {
    margin-top: 0.5rem;
    color: var(--color-text-muted);
    font-size: 0.92rem;
}

/* ── Header Actions ── */
.header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.home-btn {
    display: inline-flex;
    align-items: center;
    padding: 0.35rem 0.85rem;
    border-radius: 6px;
    background: var(--color-primary);
    color: #fff;
    text-decoration: none;
    font-size: 0.82rem;
    font-weight: 600;
    transition: background var(--transition);
}
.home-btn:hover { background: var(--color-primary-dark); }

/* ── Language Switcher ── */
.lang-switcher {
    display: flex;
    gap: 0.25rem;
}

.lang-btn {
    padding: 0.3rem 0.6rem;
    border: 1.5px solid var(--color-border);
    border-radius: 5px;
    background: var(--color-surface);
    color: var(--color-text-muted);
    font-size: 0.78rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
}
.lang-btn:hover { border-color: var(--color-primary-light); color: var(--color-primary); }
.lang-btn.active {
    background: var(--color-primary);
    color: #fff;
    border-color: var(--color-primary);
}

/* ── Accent Divider ── */
.accent-divider {
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light), transparent);
    border-radius: 2px;
    margin-bottom: 1.5rem;
}

/* ── Tab Bar ── */
.tab-bar {
    display: flex;
    gap: 0.25rem;
    border-bottom: 2px solid var(--color-border);
    margin-bottom: 1.5rem;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.tab-btn {
    padding: 0.6rem 1.2rem;
    border: none;
    border-bottom: 3px solid transparent;
    background: transparent;
    color: var(--color-text-muted);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
    margin-bottom: -2px;
    transition: all var(--transition);
}
.tab-btn:hover { color: var(--color-primary); }
.tab-btn.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    font-weight: 600;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── Calc Grid ── */
.calc-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 380px;
    gap: 1.5rem;
    align-items: start;
}

@media (max-width: 900px) {
    .calc-grid { grid-template-columns: 1fr; }
    .right-panel { order: 2; }
}

/* ── Calc Section ── */
.calc-section {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: box-shadow var(--transition);
}
.calc-section:hover { box-shadow: var(--shadow-md); }

.section-header { margin-bottom: 1.25rem; }

.section-title {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.35rem;
}

.section-badge {
    display: inline-block;
    padding: 0.15rem 0.55rem;
    border-radius: 99px;
    font-size: 0.72rem;
    font-weight: 600;
    color: #fff;
}
.badge-od { background: var(--color-badge-od); }
.badge-stack { background: var(--color-badge-stack); }
.badge-laser { background: var(--color-badge-laser); }

.section-desc {
    font-size: 0.84rem;
    color: var(--color-text-muted);
}

/* ── Input Grid ── */
.input-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}
.field-full { grid-column: 1 / -1; }

.field-group {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.field-group label {
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.field-group input {
    padding: 0.55rem 0.75rem;
    border: 1.5px solid var(--color-border);
    border-radius: 7px;
    font-size: 0.95rem;
    font-family: inherit;
    color: var(--color-text);
    background: #fff;
    transition: border-color var(--transition), box-shadow var(--transition);
    width: 100%;
}
.field-group input:focus {
    outline: none;
    border-color: var(--color-primary-light);
    box-shadow: 0 0 0 3px rgba(124,58,237,0.10);
}
.field-group input.just-updated {
    border-color: var(--color-primary);
    background: #f5f0ff;
}

/* ── Reset Row ── */
.reset-row {
    display: flex;
    justify-content: flex-end;
    margin-top: 1.1rem;
}

.btn-reset {
    padding: 0.4rem 1.1rem;
    border: 1.5px solid var(--color-border);
    border-radius: 6px;
    background: var(--color-surface);
    color: var(--color-text-muted);
    font-size: 0.83rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
}
.btn-reset:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background: #f5f0ff;
}

/* ── Stack Inputs ── */
.stack-inputs { display: flex; flex-direction: column; gap: 0.75rem; margin-bottom: 1rem; }

.stack-filter-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.stack-filter-label {
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--color-text-muted);
    white-space: nowrap;
    min-width: 64px;
}

.stack-filter-row input {
    flex: 1;
    padding: 0.55rem 0.75rem;
    border: 1.5px solid var(--color-border);
    border-radius: 7px;
    font-size: 0.95rem;
    font-family: inherit;
    color: var(--color-text);
    background: #fff;
    transition: border-color var(--transition), box-shadow var(--transition);
}
.stack-filter-row input:focus {
    outline: none;
    border-color: var(--color-primary-light);
    box-shadow: 0 0 0 3px rgba(124,58,237,0.10);
}

.btn-remove-filter {
    padding: 0.3rem 0.55rem;
    border: 1.5px solid #fca5a5;
    border-radius: 6px;
    background: #fff;
    color: #ef4444;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all var(--transition);
    flex-shrink: 0;
}
.btn-remove-filter:hover { background: #fee2e2; }

.stack-add-row { margin-bottom: 1.25rem; }

.btn-add-filter {
    padding: 0.45rem 1.1rem;
    border: 1.5px dashed var(--color-primary-light);
    border-radius: 7px;
    background: #f5f0ff;
    color: var(--color-primary);
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
}
.btn-add-filter:hover { background: #ede9fe; border-color: var(--color-primary); }

/* ── Stack Result Card ── */
.stack-result-card {
    background: linear-gradient(135deg, #f5f0ff 0%, #ede9fe 100%);
    border: 1.5px solid var(--color-primary-light);
    border-radius: var(--radius);
    padding: 1.1rem 1.25rem;
    margin-bottom: 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.stack-result-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.stack-result-label {
    font-size: 0.84rem;
    font-weight: 500;
    color: var(--color-primary-dark);
}

.stack-result-value {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--color-primary);
    font-variant-numeric: tabular-nums;
}

/* ── Laser Grid ── */
.laser-od-row { margin-bottom: 1.25rem; }

.laser-grid {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1rem;
    align-items: center;
    margin-bottom: 0.5rem;
}

.laser-col { display: flex; flex-direction: column; gap: 0.75rem; }

.laser-col-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-primary);
    text-align: center;
    padding: 0.3rem;
    background: #f5f0ff;
    border-radius: 6px;
}

.laser-arrow {
    font-size: 1.5rem;
    color: var(--color-primary-light);
    text-align: center;
    font-weight: 300;
}

@media (max-width: 600px) {
    .laser-grid {
        grid-template-columns: 1fr;
    }
    .laser-arrow { display: none; }
}

/* ── Right Panel ── */
.right-panel { display: flex; flex-direction: column; gap: 1.25rem; }

/* ── Knowledge Card ── */
.knowledge-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.25rem;
    box-shadow: var(--shadow);
}

.knowledge-card h2 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1.5px solid #ede9fe;
}

.knowledge-block { margin-bottom: 0.9rem; }
.knowledge-block h3 {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.25rem;
}
.knowledge-block p {
    font-size: 0.82rem;
    color: var(--color-text-muted);
    line-height: 1.5;
}

/* ── Conv Table ── */
.conv-table-title {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--color-text);
    margin: 0.9rem 0 0.5rem;
}

.conv-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.8rem;
}
.conv-table th {
    background: #f5f0ff;
    color: var(--color-primary-dark);
    font-weight: 600;
    padding: 0.45rem 0.6rem;
    text-align: left;
    border-bottom: 1.5px solid #ddd6fe;
}
.conv-table td {
    padding: 0.4rem 0.6rem;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text);
    font-variant-numeric: tabular-nums;
}
.conv-table tr:hover td { background: #f5f0ff; }
.conv-table tr:last-child td { border-bottom: none; }

/* ── FAQ Card ── */
.faq-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.25rem;
    box-shadow: var(--shadow);
}

.faq-card h2 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1.5px solid #ede9fe;
}

.faq-item { margin-bottom: 0.9rem; }
.faq-item:last-child { margin-bottom: 0; }
.faq-item h3 {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 0.2rem;
}
.faq-item p {
    font-size: 0.81rem;
    color: var(--color-text-muted);
    line-height: 1.5;
}

/* ── Footer ── */
footer {
    margin-top: 2.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-text-muted);
}
footer a {
    color: var(--color-primary);
    text-decoration: none;
}
footer a:hover { text-decoration: underline; }

/* ── Responsive ── */
@media (max-width: 600px) {
    .input-grid { grid-template-columns: 1fr; }
    .field-full { grid-column: auto; }
    .tab-btn { padding: 0.5rem 0.85rem; font-size: 0.83rem; }
    .calc-section { padding: 1.1rem; }
}