:root {
--page-bg: #f8fafc;
--primary-color: #3b82f6;
--primary-hover: #2563eb;
--primary-soft: rgba(59, 130, 246, 0.12);
--surface-color: #ffffff;
--surface-muted: #fefefe;
--surface-border: #e2e8f0;
--text-primary: #0f172a;
--text-secondary: #475569;
--text-helper: #64748b;
--accent-success: #10b981;
--accent-warning: #f59e0b;
--accent-info: #0ea5e9;
--accent-purple: #8b5cf6;
--shadow-sm: 0 8px 24px rgba(15, 23, 42, 0.08);
--shadow-md: 0 20px 40px rgba(15, 23, 42, 0.10);
--radius-sm: 0.5rem;
--radius-md: 1rem;
--radius-lg: 1.5rem;
}

.calculator-page {
padding: clamp(1.5rem, 3vw, 2.5rem) 0 clamp(1.5rem, 3vw, 1.5rem);
color: var(--text-primary);
}

.calculator-container {
margin: 0 auto;
}

.page-hero {
display: grid;
gap: 1.5rem;
margin-bottom: clamp(2rem, 5vw, 3.5rem);
text-align: left;
}

.page-hero__title {
font-size: clamp(2rem, 4vw, 3rem);
font-weight: 800;
line-height: 1.1;
color: var(--text-primary);
margin: 0;
}

.page-hero__subtitle {
margin: 0;
font-size: clamp(1.05rem, 2.6vw, 1.25rem);
line-height: 1.6;
color: var(--text-secondary);
max-width: 90ch;
}

.badge-row {
display: flex;
flex-wrap: wrap;
gap: 0.6rem;
}

.badge {
background: var(--surface-color);
border: 1px solid rgba(15, 23, 42, 0.08);
color: var(--text-helper);
padding: 0.4rem 0.9rem;
border-radius: 9999px;
font-size: 0.9rem;
line-height: 1.5;
font-weight: 600;
box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
}

.calculator-shell {
display: grid;
gap: clamp(1.5rem, 4vw, 2.25rem);
}

.calculator-grid {
display: grid;
gap: clamp(1.5rem, 4vw, 2.5rem);
}

.card {
background: var(--surface-color);
border-radius: var(--radius-lg);
padding: clamp(1.5rem, 4vw, 2.5rem);
box-shadow: var(--shadow-sm);
border: 1px solid rgba(148, 163, 184, 0.18);
}

.card__header {
display: flex;
flex-direction: column;
gap: 0.5rem;
margin-bottom: 1.5rem;
}

.card__title {
font-size: clamp(1.45rem, 3vw, 1.8rem);
font-weight: 700;
margin: 0;
color: var(--text-primary);
}

.card__blurb {
margin: 0;
font-size: 1rem;
color: var(--text-helper);
line-height: 1.55;
}

.drake-equation-display {
background: linear-gradient(135deg, rgba(59, 130, 246, 0.08), rgba(139, 92, 246, 0.08));
border: 1px solid rgba(59, 130, 246, 0.2);
border-radius: var(--radius-md);
padding: 1.5rem;
margin-bottom: 2rem;
text-align: center;
}

.equation-formula {
font-size: clamp(1.2rem, 3vw, 1.6rem);
font-weight: 700;
color: var(--primary-color);
margin: 0 0 0.5rem;
}

.equation-description {
font-size: 0.95rem;
color: var(--text-helper);
margin: 0;
}

.form-grid {
display: grid;
gap: 1.5rem;
}

.input-group {
border: 1px solid var(--surface-border);
border-radius: var(--radius-md);
padding: 1.25rem;
background: var(--surface-muted);
}

.input-group__title {
margin: 0 0 1rem;
font-size: 1.05rem;
font-weight: 700;
display: flex;
align-items: center;
gap: 0.5rem;
color: var(--text-primary);
}

.field-grid {
display: grid;
gap: 1rem;
}

@media (min-width: 640px) {
.field-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}
}

.field {
display: flex;
flex-direction: column;
gap: 0.45rem;
}

.field__label {
font-size: 0.9rem;
font-weight: 600;
color: var(--text-primary);
display: flex;
align-items: center;
justify-content: space-between;
gap: 0.5rem;
}

.field__control {
width: 100%;
padding: 1rem 1.1rem;
font-size: 1.05rem;
border-radius: var(--radius-sm);
border: 2px solid var(--surface-border);
background: var(--surface-color);
color: var(--text-primary);
transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.field__control:focus {
border-color: var(--primary-color);
box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
outline: none;
}

.field__control:hover {
border-color: rgba(59, 130, 246, 0.6);
}

.field__help {
font-size: 0.85rem;
color: var(--text-helper);
line-height: 1.4;
}

.preset-chips {
display: flex;
flex-wrap: wrap;
gap: 0.75rem;
margin-top: 1rem;
}

.preset-chip {
border-radius: 999px;
border: 1px solid rgba(59, 130, 246, 0.25);
background: rgba(59, 130, 246, 0.08);
color: var(--primary-hover);
font-weight: 600;
font-size: 0.9rem;
padding: 0.5rem 0.95rem;
cursor: pointer;
transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.preset-chip:hover,
.preset-chip:focus {
transform: translateY(-1px);
box-shadow: 0 8px 18px rgba(59, 130, 246, 0.18);
}

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

.button-row {
display: flex;
flex-wrap: wrap;
gap: 0.75rem;
}

.button {
border-radius: var(--radius-sm);
border: none;
padding: 0.95rem 1.4rem;
font-size: 1rem;
font-weight: 600;
cursor: pointer;
transition: transform 0.2s ease, box-shadow 0.2s ease;
display: inline-flex;
align-items: center;
gap: 0.6rem;
justify-content: center;
}

.button:focus {
outline: 2px solid rgba(59, 130, 246, 0.4);
outline-offset: 3px;
}

.button-primary {
background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
color: #fff;
box-shadow: 0 12px 24px rgba(59, 130, 246, 0.18);
}

.button-primary:hover {
transform: translateY(-2px);
box-shadow: 0 16px 30px rgba(59, 130, 246, 0.22);
}

.button-ghost {
background: transparent;
border: 2px solid var(--surface-border);
color: var(--text-secondary);
}

.button-ghost:hover {
border-color: rgba(59, 130, 246, 0.45);
color: var(--primary-color);
transform: translateY(-2px);
}

.button-neutral {
background: var(--surface-muted);
color: var(--text-primary);
border: 1px solid rgba(148, 163, 184, 0.35);
}

.results-card {
display: grid;
gap: 1.5rem;
}

.results-header {
display: flex;
flex-direction: column;
gap: 0.5rem;
}

.results-badge {
align-self: flex-start;
background: rgba(59, 130, 246, 0.12);
color: var(--primary-hover);
padding: 0.3rem 0.8rem;
border-radius: 9999px;
font-size: 0.85rem;
font-weight: 600;
}

.result-expression {
font-size: clamp(1.3rem, 2.8vw, 1.7rem);
font-weight: 700;
margin: 0;
color: var(--text-primary);
word-break: break-word;
}

.result-summary {
margin: 0;
font-size: 1rem;
color: var(--text-helper);
line-height: 1.6;
}

.metrics-grid {
display: grid;
gap: 1rem;
}

@media (min-width: 640px) {
.metrics-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}
}

.metric-card {
border-radius: var(--radius-md);
border: 1px solid rgba(148, 163, 184, 0.22);
background: var(--surface-muted);
padding: 1.2rem 1.3rem;
display: grid;
gap: 0.35rem;
}

.metric-label {
font-size: 0.8rem;
text-transform: uppercase;
letter-spacing: 0.08em;
font-weight: 700;
color: var(--text-helper);
}

.metric-value {
font-size: 1.25rem;
font-weight: 700;
color: var(--text-primary);
}

.civilization-count {
font-size: clamp(2.5rem, 6vw, 4rem);
font-weight: 800;
color: var(--primary-color);
text-align: center;
margin: 1rem 0;
line-height: 1;
}

.interpretation-panel {
border-radius: var(--radius-md);
border: 1px dashed rgba(59, 130, 246, 0.25);
padding: 1.15rem 1.3rem;
background: rgba(59, 130, 246, 0.05);
margin-top: 1rem;
}

.interpretation-panel__title {
margin: 0 0 0.8rem;
font-size: 1.05rem;
font-weight: 700;
color: var(--text-primary);
}

.interpretation-text {
margin: 0;
font-size: 0.98rem;
color: var(--text-helper);
line-height: 1.55;
}

.result-actions {
display: flex;
flex-wrap: wrap;
gap: 0.75rem;
}

.result-actions .button {
flex: 1 1 220px;
}

.education-section {
margin-top: clamp(3rem, 7vw, 4.5rem);
display: grid;
gap: clamp(2rem, 6vw, 3rem);
}

.seo-article {
background: var(--surface-color);
border-radius: var(--radius-lg);
border: 1px solid rgba(148, 163, 184, 0.18);
padding: clamp(1.8rem, 4vw, 2.5rem);
box-shadow: var(--shadow-sm);
}

.seo-article h2,
.seo-article h3 {
color: var(--text-primary);
font-weight: 700;
}

.seo-article p {
color: var(--text-helper);
line-height: 1.75;
font-size: 1rem;
margin-bottom: 1.1rem;
}

.related-tools {
background: var(--surface-color);
border-radius: var(--radius-md);
border: 1px solid rgba(148, 163, 184, 0.22);
padding: 1.75rem;
}

.related-tools__title {
margin: 0 0 1rem;
font-size: 1.15rem;
font-weight: 700;
}

.related-tools__list {
list-style: none;
padding: 0;
margin: 0;
display: grid;
gap: 0.75rem 1.25rem;
grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
align-items: start;
}

@media (min-width: 768px) {
.related-tools__list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}
}

.related-tools__list a {
color: var(--primary-hover);
font-weight: 600;
text-decoration: none;
}

.related-tools__list a:hover {
text-decoration: underline;
}

.faq-container {
background: var(--surface-color);
border-radius: var(--radius-lg);
border: 1px solid rgba(148, 163, 184, 0.18);
padding: clamp(1.8rem, 4vw, 2.4rem);
box-shadow: var(--shadow-sm);
}

.faq-item {
padding: 1.1rem 0;
border-bottom: 1px solid rgba(148, 163, 184, 0.18);
}

.faq-item:last-child {
border-bottom: none;
}

.faq-question {
margin: 0 0 0.45rem;
font-size: 1rem;
font-weight: 600;
color: var(--text-primary);
}

.faq-answer {
margin: 0;
font-size: 0.85rem;
line-height: 1.65;
color: var(--text-helper);
}

.sr-only {
position: absolute;
width: 1px;
height: 1px;
padding: 0;
margin: -1px;
overflow: hidden;
clip: rect(0, 0, 0, 0);
white-space: nowrap;
border: 0;
}

@media (min-width: 1024px) {
.calculator-grid {
    grid-template-columns: 1fr 1fr;
    align-items: start;
}
}

@media (prefers-reduced-motion: reduce) {
*, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
}
}

.result-highlight {
animation: fadePulse 0.85s ease;
}

@keyframes fadePulse {
0% { background-color: rgba(59, 130, 246, 0.05); }
60% { background-color: rgba(59, 130, 246, 0.15); }
100% { background-color: transparent; }
}

.share-modal {
display: none;
position: fixed;
z-index: 1000;
left: 0;
top: 0;
width: 100%;
height: 100%;
background-color: rgba(0, 0, 0, 0.5);
}

.share-modal-content {
background-color: #ffffff;
margin: 15% auto;
padding: 3rem 4rem;
border-radius: 8px;
width: 90%;
max-width: 750px;
position: relative;
}

.share-modal-close {
position: absolute;
right: 3rem;
top: 3rem;
font-size: 1.5rem;
font-weight: bold;
cursor: pointer;
color: #9ca3af;
}

.share-modal-close:hover {
color: #374151;
}

.share-url-container {
display: flex;
gap: 0.5rem;
margin-top: 1rem;
}

.share-url-input {
flex: 1;
padding: 0.75rem;
border: 1px solid #d1d5db;
border-radius: 6px;
font-size: 0.875rem;
}

.btn-copy-url {
padding: 0.75rem 1rem;
background: var(--primary-color);
color: #ffffff;
border: none;
border-radius: 6px;
cursor: pointer;
font-size: 0.875rem;
font-weight: 500;
}

.btn-copy-url:hover {
background: var(--primary-hover);
}