/* ============================================
   FRACTURED RESEARCH — Design System
   ============================================ */

:root {
  /* Palette */
  --color-bg:        #faf9f6;
  --color-surface:   #ffffff;
  --color-border:    #e8e4de;
  --color-border-lt: #f0ece6;
  --color-text:      #2c2825;
  --color-text-mid:  #6b6560;
  --color-text-lt:   #9a9490;
  --color-accent:    #8b5e3c;
  --color-accent-hover: #a0714f;
  --color-accent-bg: #f5efe8;
  --color-tag-bg:    #eee9e2;
  --color-tag-text:  #6b5d52;
  --color-danger:    #c0392b;
  --color-success:   #27ae60;

  /* Typography */
  --font-serif:  'Playfair Display', 'Georgia', serif;
  --font-sans:   'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono:   'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2.5rem;
  --space-2xl: 4rem;

  /* Layout */
  --max-width: 780px;
  --nav-height: 64px;

  /* Transitions */
  --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  min-height: 100vh;
}

a { color: var(--color-accent); text-decoration: none; }
a:hover { color: var(--color-accent-hover); }

/* ============================================
   Navigation
   ============================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(250, 249, 246, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-lt);
  z-index: 100;
  transition: box-shadow 0.3s var(--ease);
}

.nav.scrolled {
  box-shadow: 0 1px 8px rgba(0,0,0,0.06);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text);
  font-weight: 600;
  transition: opacity 0.2s;
}

.nav-logo:hover { opacity: 0.7; color: var(--color-text); }

.logo-mark {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-accent);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--color-accent);
  border-radius: 8px;
}

.logo-text {
  font-size: 0.95rem;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: var(--space-xs);
}

.nav-link {
  padding: var(--space-sm) var(--space-md);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-mid);
  border-radius: 8px;
  transition: all 0.2s var(--ease);
}

.nav-link:hover {
  color: var(--color-text);
  background: var(--color-accent-bg);
}

.nav-link.active {
  color: var(--color-accent);
  background: var(--color-accent-bg);
}

/* ============================================
   Main Layout
   ============================================ */

.main {
  max-width: 1100px;
  margin: 0 auto;
  padding: calc(var(--nav-height) + var(--space-xl)) var(--space-lg) var(--space-2xl);
  min-height: 100vh;
}

.page {
  display: none;
  animation: fadeIn 0.35s var(--ease);
}

.page.active { display: block; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---- Page Header ---- */

.page-header {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.page-title {
  font-family: var(--font-serif);
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
  color: var(--color-text);
}

.page-subtitle {
  margin-top: var(--space-sm);
  font-size: 1.05rem;
  color: var(--color-text-mid);
  font-weight: 300;
}

/* ============================================
   Search
   ============================================ */

.search-bar {
  position: relative;
  margin-top: var(--space-lg);
  max-width: 420px;
}

.search-icon {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  color: var(--color-text-lt);
  pointer-events: none;
}

.search-bar input {
  width: 100%;
  padding: 10px 16px 10px 42px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color 0.2s, box-shadow 0.2s;
  outline: none;
}

.search-bar input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(139, 94, 60, 0.1);
}

.search-bar input::placeholder {
  color: var(--color-text-lt);
}

/* ============================================
   Filter Chips
   ============================================ */

.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.filter-chip {
  padding: 6px 16px;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  border: 1px solid transparent;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.2s var(--ease);
}

.filter-chip:hover {
  background: var(--color-border);
  color: var(--color-text);
}

.filter-chip.active {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

/* ============================================
   Article Cards
   ============================================ */

.article-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.article-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-lt);
  border-radius: 12px;
  padding: var(--space-lg) var(--space-xl);
  cursor: pointer;
  transition: all 0.25s var(--ease);
  position: relative;
}

.article-card:hover {
  border-color: var(--color-border);
  box-shadow: 0 4px 20px rgba(0,0,0,0.04);
  transform: translateY(-2px);
}

/* ---- Hero Card ---- */

.article-card-hero {
  padding: var(--space-xl);
  border-left: 3px solid var(--color-accent);
}

.article-card-hero .article-card-title {
  font-size: 1.8rem;
  line-height: 1.3;
  margin-bottom: var(--space-sm);
}

.article-card-hero .article-card-abstract {
  -webkit-line-clamp: unset;
  font-size: 1rem;
  line-height: 1.7;
}

/* ---- Grid ---- */

.article-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}

.article-card-grid {
  padding: var(--space-md) var(--space-lg);
}

.article-card-grid .article-card-title {
  font-size: 1rem;
  line-height: 1.3;
}

.article-card-grid .article-card-abstract {
  font-size: 0.85rem;
  -webkit-line-clamp: 2;
}

.article-card-grid .article-card-meta {
  gap: var(--space-sm);
  font-size: 0.72rem;
}

.article-card-grid .article-card-category {
  font-size: 0.68rem;
}

.article-card-grid .tag {
  font-size: 0.68rem;
  padding: 2px 8px;
}

/* ---- Shared card elements ---- */

.article-card-meta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-size: 0.8rem;
  color: var(--color-text-lt);
  margin-bottom: var(--space-sm);
}

.article-card-category {
  font-weight: 500;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 0.75rem;
}

.article-card-dot {
  width: 3px;
  height: 3px;
  background: var(--color-text-lt);
  border-radius: 50%;
}

.article-card-title {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 600;
  line-height: 1.35;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  transition: color 0.2s;
}

.article-card:hover .article-card-title {
  color: var(--color-accent);
}

.article-card-abstract {
  font-size: 0.925rem;
  color: var(--color-text-mid);
  line-height: 1.65;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card-footer {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-md);
  flex-wrap: wrap;
}

.tag {
  display: inline-block;
  padding: 3px 10px;
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  border-radius: 20px;
  letter-spacing: 0.01em;
}

/* ============================================
   Article Reader
   ============================================ */

.reader {
  max-width: var(--max-width);
  margin: 0 auto;
}

.reader-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-mid);
  margin-bottom: var(--space-xl);
  transition: color 0.2s;
  cursor: pointer;
  background: none;
  border: none;
  font-family: var(--font-sans);
}

.reader-back:hover { color: var(--color-accent); }

.reader-back svg {
  width: 18px;
  height: 18px;
}

.reader-header {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.reader-category {
  font-weight: 600;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
  margin-bottom: var(--space-sm);
}

.reader-title {
  font-family: var(--font-serif);
  font-size: 2.4rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

.reader-meta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-size: 0.875rem;
  color: var(--color-text-lt);
}

.reader-meta strong {
  color: var(--color-text-mid);
  font-weight: 500;
}

.reader-abstract {
  font-size: 1.1rem;
  font-style: italic;
  color: var(--color-text-mid);
  line-height: 1.7;
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-border-lt);
  margin-bottom: var(--space-xl);
  font-family: var(--font-serif);
}

.reader-body {
  font-size: 1.05rem;
  line-height: 1.85;
  color: var(--color-text);
}

.reader-body h1,
.reader-body h2,
.reader-body h3 {
  font-family: var(--font-serif);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
  line-height: 1.3;
}

.reader-body h2 { font-size: 1.5rem; }
.reader-body h3 { font-size: 1.2rem; }

.reader-body p {
  margin-bottom: var(--space-md);
}

.reader-body ul, .reader-body ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-lg);
}

.reader-body li {
  margin-bottom: var(--space-sm);
}

.reader-body blockquote {
  border-left: 3px solid var(--color-accent);
  padding: var(--space-sm) var(--space-lg);
  margin: var(--space-lg) 0;
  font-style: italic;
  color: var(--color-text-mid);
  background: var(--color-accent-bg);
  border-radius: 0 8px 8px 0;
}

.reader-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--color-tag-bg);
  padding: 2px 6px;
  border-radius: 4px;
}

.reader-body pre {
  background: #2c2825;
  color: #e8e4de;
  padding: var(--space-lg);
  border-radius: 10px;
  overflow-x: auto;
  margin: var(--space-lg) 0;
  line-height: 1.5;
}

.reader-body pre code {
  background: none;
  padding: 0;
  color: inherit;
}

.reader-body strong { font-weight: 600; }
.reader-body em { font-style: italic; }

.reader-body hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-xl) 0;
}

.reader-tags {
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border-lt);
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

/* ============================================
   Compose Form
   ============================================ */

.compose-form {
  max-width: var(--max-width);
}

.form-group {
  margin-bottom: var(--space-lg);
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  letter-spacing: 0.01em;
}

.label-hint {
  font-weight: 400;
  color: var(--color-text-lt);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 10px 14px;
  font-family: var(--font-sans);
  font-size: 0.925rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-surface);
  color: var(--color-text);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group textarea {
  resize: vertical;
  line-height: 1.7;
}

.form-group textarea#compose-body {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(139, 94, 60, 0.1);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
}

.form-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: flex-end;
  padding-top: var(--space-md);
}

.btn {
  padding: 10px 24px;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s var(--ease);
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  box-shadow: 0 2px 12px rgba(139, 94, 60, 0.25);
}

.btn-secondary {
  background: var(--color-tag-bg);
  color: var(--color-text-mid);
}

.btn-secondary:hover {
  background: var(--color-border);
}

/* ============================================
   About
   ============================================ */

.about-content {
  max-width: var(--max-width);
}

.about-section {
  margin-bottom: var(--space-xl);
}

.about-section h2 {
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.about-section p {
  font-size: 1.025rem;
  line-height: 1.8;
  color: var(--color-text-mid);
}

.about-divider {
  width: 60px;
  height: 2px;
  background: var(--color-accent);
  margin: var(--space-xl) 0;
  border-radius: 1px;
}

.about-footer {
  font-size: 0.9rem;
  color: var(--color-text-lt);
  font-style: italic;
}

/* ============================================
   Simulation Page
   ============================================ */

.sim-layout {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.sim-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border-lt);
  border-radius: 12px;
  padding: var(--space-lg) var(--space-xl);
}

.sim-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border-lt);
}

.sim-panel-header h3 {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-text);
}

/* Tabs */
.sim-tabs {
  display: flex;
  gap: var(--space-xs);
  margin-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border-lt);
  padding-bottom: var(--space-xs);
}

.sim-tab-btn {
  padding: var(--space-sm) var(--space-md);
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-mid);
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: all 0.2s var(--ease);
  border-radius: 6px 6px 0 0;
}

.sim-tab-btn:hover {
  color: var(--color-text);
  background: var(--color-accent-bg);
}

.sim-tab-btn.active {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

.sim-tab-panel {
  display: none;
}

.sim-tab-panel.active {
  display: block;
  animation: fadeIn 0.2s var(--ease);
}

/* Form Grid */
.sim-form-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md) var(--space-lg);
}

.sim-field {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.sim-field-full {
  grid-column: 1 / -1;
}

.sim-field label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--color-text-mid);
  letter-spacing: 0.01em;
}

.sim-unit {
  font-weight: 400;
  color: var(--color-text-lt);
  font-size: 0.75rem;
}

.sim-input {
  width: 100%;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-bg);
  color: var(--color-text);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.sim-input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(139, 94, 60, 0.1);
}

.sim-input-sm {
  padding: 5px 8px;
  font-size: 0.8rem;
}

select.sim-input {
  font-family: var(--font-sans);
  cursor: pointer;
}

/* Pump Schedule Table */
.sim-schedule-wrapper {
  overflow-x: auto;
}

.sim-schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.sim-schedule-table th {
  text-align: left;
  font-weight: 600;
  font-size: 0.78rem;
  color: var(--color-text-mid);
  padding: var(--space-sm) var(--space-xs);
  border-bottom: 2px solid var(--color-border);
  white-space: nowrap;
}

.sim-schedule-table td {
  padding: var(--space-xs);
  border-bottom: 1px solid var(--color-border-lt);
}

.sim-schedule-table .sim-input-sm {
  min-width: 60px;
}

.sim-schedule-table select.sim-input-sm {
  min-width: 130px;
}

.sim-schedule-table td:first-child .sim-input-sm {
  min-width: 80px;
}

.sim-row-delete {
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--color-text-lt);
  cursor: pointer;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.sim-row-delete:hover {
  background: #fde8e8;
  color: var(--color-danger);
}

.sim-add-row {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: var(--space-md);
}

/* Run Button */
.sim-run-section {
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border-lt);
  display: flex;
  justify-content: center;
}

.btn-lg {
  padding: 14px 40px;
  font-size: 1rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
}

.btn-sm {
  padding: 6px 14px;
  font-size: 0.8rem;
}

/* Results Summary */
.sim-summary {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.sim-stat-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border-lt);
  border-radius: 10px;
  padding: var(--space-md);
  text-align: center;
  transition: border-color 0.2s;
}

.sim-stat-card:hover {
  border-color: var(--color-accent);
}

.sim-stat-value {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.2;
}

.sim-stat-unit {
  font-size: 0.7rem;
  font-weight: 400;
  color: var(--color-text-lt);
  margin-left: 2px;
}

.sim-stat-label {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--color-text-lt);
  margin-top: var(--space-xs);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* Charts */
.sim-charts {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.sim-chart-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
}

.sim-chart-container {
  background: var(--color-surface);
  border: 1px solid var(--color-border-lt);
  border-radius: 10px;
  overflow: hidden;
}

.sim-chart-container canvas {
  width: 100%;
  height: 300px;
  display: block;
}

.sim-chart-wide canvas {
  height: 380px;
}

/* ============================================
   Empty State
   ============================================ */

.empty-state {
  text-align: center;
  padding: var(--space-2xl) 0;
  color: var(--color-text-lt);
}

.empty-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--space-md);
  opacity: 0.4;
}

.empty-state p {
  font-size: 1rem;
}

/* ============================================
   Toast Notification
   ============================================ */

.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-text);
  color: var(--color-bg);
  padding: 12px 24px;
  border-radius: 10px;
  font-size: 0.9rem;
  font-weight: 500;
  box-shadow: 0 8px 30px rgba(0,0,0,0.15);
  opacity: 0;
  transition: all 0.35s var(--ease);
  z-index: 200;
  pointer-events: none;
}

.toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 1024px) {
  .article-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .nav-inner { padding: 0 var(--space-md); }
  .logo-text { display: none; }
  .main { padding-left: var(--space-md); padding-right: var(--space-md); }
  .page-title { font-size: 1.75rem; }
  .reader-title { font-size: 1.8rem; }
  .article-card { padding: var(--space-md) var(--space-lg); }
  .article-card-hero .article-card-title { font-size: 1.4rem; }
  .article-card-grid .article-card-title { font-size: 0.95rem; }
  .article-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .sim-form-grid { grid-template-columns: 1fr; }
  .sim-chart-row { grid-template-columns: 1fr; }
  .sim-summary { grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); }
  .sim-panel { padding: var(--space-md); }
  .sim-chart-container canvas { height: 240px; }
  .sim-chart-wide canvas { height: 280px; }
}

@media (max-width: 480px) {
  .nav-links { gap: 0; }
  .nav-link { padding: var(--space-sm) var(--space-sm); font-size: 0.8rem; }
  .page-title { font-size: 1.5rem; }
  .reader-title { font-size: 1.5rem; }
  .reader-abstract { font-size: 1rem; }
}