/* ============================================================
   LLM Context Planner — Stylesheet
   Tech/developer aesthetic: dark-first, monospace accents,
   precise grid, teal primary
   ============================================================ */

/* ── Design Tokens ── */
:root,
[data-theme='light'] {
  --font-display: 'Geist Mono', 'Courier New', monospace;
  --font-body: 'Cabinet Grotesk', 'Helvetica Neue', sans-serif;

  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.5rem);

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Light palette — cool slate surfaces with teal accent */
  --color-bg: #f4f5f7;
  --color-surface: #ffffff;
  --color-surface-2: #f9fafb;
  --color-surface-offset: #eef0f3;
  --color-divider: #e2e5ea;
  --color-border: #d1d5db;
  --color-text: #111827;
  --color-text-muted: #6b7280;
  --color-text-faint: #9ca3af;
  --color-text-inverse: #f9fafb;

  --color-primary: #0891b2;
  --color-primary-hover: #0e7490;
  --color-primary-active: #155e75;
  --color-primary-highlight: #cffafe;

  --color-success: #059669;
  --color-warning: #d97706;
  --color-error: #dc2626;

  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 12px rgb(0 0 0 / 0.08);
  --shadow-lg: 0 12px 32px rgb(0 0 0 / 0.12);

  --content-narrow: 720px;
  --content-default: 1100px;
  --content-wide: 1300px;
}

[data-theme='dark'] {
  --color-bg: #0f1117;
  --color-surface: #161b22;
  --color-surface-2: #1c2128;
  --color-surface-offset: #21262d;
  --color-divider: #21262d;
  --color-border: #30363d;
  --color-text: #e6edf3;
  --color-text-muted: #8b949e;
  --color-text-faint: #484f58;
  --color-text-inverse: #0f1117;

  --color-primary: #38bdf8;
  --color-primary-hover: #7dd3fc;
  --color-primary-active: #bae6fd;
  --color-primary-highlight: #0c4a6e;

  --color-success: #3fb950;
  --color-warning: #d29922;
  --color-error: #f85149;

  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.3);
  --shadow-md: 0 4px 12px rgb(0 0 0 / 0.4);
  --shadow-lg: 0 12px 32px rgb(0 0 0 / 0.5);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #0f1117;
    --color-surface: #161b22;
    --color-surface-2: #1c2128;
    --color-surface-offset: #21262d;
    --color-divider: #21262d;
    --color-border: #30363d;
    --color-text: #e6edf3;
    --color-text-muted: #8b949e;
    --color-text-faint: #484f58;
    --color-text-inverse: #0f1117;
    --color-primary: #38bdf8;
    --color-primary-hover: #7dd3fc;
    --color-primary-active: #bae6fd;
    --color-primary-highlight: #0c4a6e;
    --color-success: #3fb950;
    --color-warning: #d29922;
    --color-error: #f85149;
    --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.3);
    --shadow-md: 0 4px 12px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 12px 32px rgb(0 0 0 / 0.5);
  }
}

/* ── Base Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-16);
}
body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background: var(--color-bg);
}
img, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; color: inherit; }
h1, h2, h3, h4, h5, h6 { text-wrap: balance; line-height: 1.2; }
p, li { text-wrap: pretty; }
button { cursor: pointer; background: none; border: none; }
::selection { background: var(--color-primary-highlight); color: var(--color-text); }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: var(--radius-sm); }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}
a, button, [role='button'], input, textarea, select {
  transition: color var(--transition-interactive), background var(--transition-interactive),
    border-color var(--transition-interactive), box-shadow var(--transition-interactive),
    opacity var(--transition-interactive);
}

/* ── Layout ── */
.container {
  width: 100%;
  max-width: var(--content-default);
  margin-inline: auto;
  padding-inline: var(--space-6);
}
.container-narrow { max-width: var(--content-narrow); }

/* ── Header ── */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-divider);
  backdrop-filter: blur(8px);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding: var(--space-3) var(--space-6);
}
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--color-text);
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: -0.02em;
}
.logo-accent { color: var(--color-primary); }
.header-nav { display: flex; align-items: center; gap: var(--space-3); }

/* ── Hero ── */
.hero {
  padding: var(--space-12) 0 var(--space-10);
  border-bottom: 1px solid var(--color-divider);
}
.hero-eyebrow {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-primary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: var(--space-3);
}
.hero-title {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--color-text);
  margin-bottom: var(--space-4);
}
.hero-sub {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 60ch;
  line-height: 1.7;
}

/* ── Tool Section ── */
.tool-section { padding: var(--space-10) 0; }
.tool-grid {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: var(--space-8);
  align-items: start;
}
@media (max-width: 900px) {
  .tool-grid { grid-template-columns: 1fr; }
}

/* ── Input Panel ── */
.panel-inputs {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.input-group { display: flex; flex-direction: column; gap: var(--space-2); }
.input-label {
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-3) center;
  padding-right: var(--space-8);
  cursor: pointer;
}
.select:hover { border-color: var(--color-primary); }

.model-meta {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.model-meta-item {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-family: var(--font-display);
}
.model-meta-item strong { color: var(--color-text); }
.model-meta-badge {
  display: inline-block;
  align-self: flex-start;
  width: fit-content;
  font-size: var(--text-xs);
  font-family: var(--font-display);
  color: var(--color-text-faint);
  background: var(--color-surface-offset);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: 0.1rem var(--space-2);
  letter-spacing: 0.02em;
  margin-top: var(--space-1);
}

/* Accordion */
.accordion {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.accordion-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  cursor: pointer;
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-text);
  list-style: none;
  user-select: none;
  letter-spacing: -0.01em;
}
.accordion-header::-webkit-details-marker { display: none; }
.accordion-header:hover { background: var(--color-surface-offset); }
.accordion-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--dot-color);
  flex-shrink: 0;
}
.accordion-tokens {
  margin-left: auto;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: 400;
}
.accordion-body {
  padding: var(--space-3) var(--space-4) var(--space-4);
  border-top: 1px solid var(--color-divider);
}

.textarea {
  width: 100%;
  padding: var(--space-3);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  color: var(--color-text);
  resize: vertical;
  line-height: 1.6;
  font-family: var(--font-display);
}
.textarea::placeholder { color: var(--color-text-faint); }
.textarea:focus { border-color: var(--color-primary); outline: none; }

/* Sliders */
.slider-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-2);
}
.slider-label { font-size: var(--text-xs); color: var(--color-text-muted); }
.slider-value {
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-primary);
  min-width: 3ch;
  text-align: right;
}
.slider {
  width: 100%;
  accent-color: var(--color-primary);
  cursor: pointer;
  height: 20px; /* larger touch target on mobile */
}
.slider-hint {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-2);
}

.input-actions {
  display: flex;
  gap: var(--space-3);
}

/* ── Output Panel ── */
.panel-output {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.output-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  box-shadow: var(--shadow-sm);
}

/* Chart */
.chart-wrap { position: relative; width: 100%; height: 80px; margin-bottom: var(--space-4); }
.chart-card { transition: border-color var(--transition-interactive); }
.chart-card.overflow { border-color: var(--color-error); }
.chart-legend {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3) var(--space-5);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}
.legend-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  flex-shrink: 0;
}

/* Summary grid */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-5);
}
@media (max-width: 600px) {
  .summary-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 900px) {
  .summary-value { font-size: var(--text-base); }
}
.summary-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.summary-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}
.summary-value {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
}
.summary-unit {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}
.cost-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-divider);
}
.cost-label { font-size: var(--text-sm); color: var(--color-text-muted); }
.cost-value {
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 700;
  color: var(--color-primary);
}

/* Status badge */
.status-card {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}
.status-icon { font-size: 1.75rem; line-height: 1; }
.status-text { display: flex; flex-direction: column; gap: var(--space-1); }
.status-text strong { font-size: var(--text-base); font-weight: 700; color: var(--color-text); }
.status-text span { font-size: var(--text-sm); color: var(--color-text-muted); }

.status-card.safe { border-color: var(--color-success); background: color-mix(in srgb, var(--color-success) 6%, var(--color-surface)); }
.status-card.caution { border-color: var(--color-warning); background: color-mix(in srgb, var(--color-warning) 6%, var(--color-surface)); }
.status-card.danger { border-color: var(--color-error); background: color-mix(in srgb, var(--color-error) 8%, var(--color-surface)); }

/* Tips */
.tips-title {
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-3);
}
.tips-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.tips-list li {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-left: var(--space-5);
  position: relative;
}
.tips-list li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-family: var(--font-display);
}

/* CTA cards */
.cta-card {
  border-color: var(--color-error);
  background: color-mix(in srgb, var(--color-error) 5%, var(--color-surface));
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.cta-label { font-size: var(--text-sm); font-weight: 600; color: var(--color-text); }
.cta-sub { font-size: var(--text-sm); color: var(--color-text-muted); }

.cta-soft-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
}
.cta-soft-label { font-size: var(--text-sm); color: var(--color-text-muted); }
.cta-soft-link {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  font-family: var(--font-display);
}
.cta-soft-link:hover { color: var(--color-primary-hover); }

/* Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  padding: var(--space-3) var(--space-5);
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  align-self: flex-start;
}
.btn-primary:hover { background: var(--color-primary-hover); }
[data-theme='dark'] .btn-primary,
:root:not([data-theme]) .btn-primary { color: var(--color-bg); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-surface);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  flex: 1;
  justify-content: center;
}
.btn-secondary:hover { border-color: var(--color-primary); color: var(--color-primary); }

.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
}
.btn-ghost:hover { background: var(--color-surface-offset); color: var(--color-text); }

/* ── Ad Slots ── */
.ad-slot { width: 100%; display: flex; justify-content: center; padding: var(--space-6) 0; }
.ad-leaderboard { background: var(--color-surface-2); border-top: 1px solid var(--color-divider); border-bottom: 1px solid var(--color-divider); }
.ad-rectangle { margin: var(--space-8) 0; }
.ad-placeholder {
  width: 100%;
  max-width: 728px;
  height: 90px;
  background: var(--color-surface-offset);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-family: var(--font-display);
}
.ad-rectangle .ad-placeholder { max-width: 336px; height: 280px; }

/* ── Content Section ── */
.content-section {
  padding: var(--space-16) 0;
  border-top: 1px solid var(--color-divider);
}
.prose {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}
.prose h2 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
  margin-top: var(--space-4);
}
.prose p, .prose li {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  line-height: 1.75;
  max-width: 68ch;
}
.prose ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-left: var(--space-5);
}
.prose ul li { position: relative; }
.prose ul li::before {
  content: '–';
  position: absolute;
  left: calc(-1 * var(--space-5));
  color: var(--color-primary);
}
.prose em { color: var(--color-text); font-style: italic; }
.prose strong { color: var(--color-text); }

/* FAQ */
.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.faq-item summary {
  padding: var(--space-4) var(--space-5);
  cursor: pointer;
  font-weight: 600;
  font-size: var(--text-sm);
  color: var(--color-text);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-family: var(--font-display);
  font-size: var(--text-base);
  color: var(--color-primary);
  flex-shrink: 0;
  margin-left: var(--space-4);
}
.faq-item[open] summary::after { content: '–'; }
.faq-item summary:hover { background: var(--color-surface-offset); }
.faq-item p {
  padding: var(--space-4) var(--space-5);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-divider);
  background: var(--color-surface-2);
  max-width: none;
}

/* ── Model Comparison Table ── */
.model-table-wrap {
  width: 100%;
  overflow-x: auto;
  margin: var(--space-5) 0 var(--space-3);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
}
.model-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}
.model-table thead {
  background: var(--color-surface-offset);
}
.model-table th {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  font-family: var(--font-display);
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--color-border);
  white-space: nowrap;
}
.model-table th:nth-child(3),
.model-table th:nth-child(4),
.model-table th:nth-child(5) {
  text-align: right;
}
.model-table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text);
  white-space: nowrap;
}
.model-table td:nth-child(3),
.model-table td:nth-child(4),
.model-table td:nth-child(5) {
  text-align: right;
  font-family: var(--font-display);
  font-size: var(--text-xs);
}
.model-table tbody tr:last-child td { border-bottom: none; }
.model-table tbody tr:hover { background: var(--color-surface-offset); }
.model-table tr.tier-ultra td:first-child strong { color: var(--color-primary); }
.model-table tr.tier-mega td:first-child strong { color: var(--color-text); }
.table-note {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-2);
}

/* ── Footer ── */
.footer {
  border-top: 1px solid var(--color-divider);
  padding: var(--space-8) 0;
  background: var(--color-surface);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-4);
}
.footer-copy { font-size: var(--text-xs); color: var(--color-text-faint); font-family: var(--font-display); }
.footer-nav { display: flex; gap: var(--space-6); }
.footer-nav a { font-size: var(--text-xs); color: var(--color-text-muted); text-decoration: none; }
.footer-nav a:hover { color: var(--color-primary); }