/* ============================================
   MINIMAL NOTION-STYLE AESTHETICS
   Crafted with precision and restraint
   ============================================ */

:root {
  /* Color palette - Light mode */
  --bg-primary: #ffffff;
  --bg-secondary: #fafaf9;
  --bg-hover: #f7f6f4;
  --text-primary: #0f0f0f;
  --text-secondary: #525252;
  --text-tertiary: #a3a3a3;
  --border-subtle: #e5e5e5;
  --border-medium: #d4d4d4;
  --accent: #0f0f0f;

  /* Typography */
  --font-sans: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, "Apple Color Emoji", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  /* Spacing - Balanced, not excessive */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 20px;
  --space-xl: 28px;
  --space-2xl: 40px;
  --space-3xl: 56px;

  /* Border radius */
  --radius-sm: 3px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-full: 999px;

  /* Shadows - Extremely subtle */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.03);
  --shadow-md: 0 2px 6px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.08);
}

/* Dark mode */
[data-theme="dark"] {
  --bg-primary: #1a1a1a;
  --bg-secondary: #242424;
  --bg-hover: #2a2a2a;
  --text-primary: #ececec;
  --text-secondary: #a3a3a3;
  --text-tertiary: #737373;
  --border-subtle: #2a2a2a;
  --border-medium: #3a3a3a;
  --accent: #ececec;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 2px 6px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.5);
}

[data-theme="dark"] .navbar {
  background: rgba(26, 26, 26, 0.85);
}

[data-theme="dark"] ::selection {
  background-color: rgba(255, 255, 255, 0.15);
}

/* ============================================
   RESET & BASE
   ============================================ */

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.65;
  font-weight: 400;
}

::selection {
  background-color: rgba(15, 15, 15, 0.06);
}

/* ============================================
   NAVIGATION
   ============================================ */

.navbar {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 100;
  padding: 0 var(--space-lg);
}

.nav-container {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 15px;
  transition: opacity 0.2s ease;
  letter-spacing: -0.01em;
}

.nav-logo:hover {
  opacity: 0.65;
}

.nav-logo svg {
  width: 22px;
  height: 22px;
  border-radius: 5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0;
}

.navbar a:not(.nav-logo) {
  display: inline-flex;
  align-items: center;
  padding: 7px 0;
  margin: 0 12px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.15s ease;
  letter-spacing: -0.005em;
  position: relative;
}

.navbar a:not(.nav-logo):hover {
  color: var(--text-primary);
}

.navbar a.active {
  color: var(--text-primary);
}

.navbar a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--text-primary);
}

.icon-link {
  padding: 8px !important;
  margin: 0 8px !important;
}

.icon-link svg {
  width: 15px;
  height: 15px;
  fill: var(--text-secondary);
  transition: fill 0.15s ease;
}

.icon-link:hover svg {
  fill: var(--text-primary);
}

/* ============================================
   LAYOUT
   ============================================ */

.content {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-3xl) var(--space-lg) var(--space-3xl);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1 {
  font-size: 40px;
  font-weight: 700;
  line-height: 1.15;
  margin: 0 0 var(--space-md) 0;
  color: var(--text-primary);
  letter-spacing: -0.035em;
}

h2 {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.25;
  margin: var(--space-3xl) 0 var(--space-lg) 0;
  color: var(--text-primary);
  letter-spacing: -0.025em;
}

h2:first-child {
  margin-top: 0;
}

h3 {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
  margin: var(--space-xl) 0 var(--space-md) 0;
  color: var(--text-primary);
  letter-spacing: -0.015em;
}

p {
  margin: 0 0 var(--space-lg) 0;
  color: var(--text-primary);
  line-height: 1.65;
  font-size: 15px;
}

.subtitle {
  font-size: 17px;
  color: var(--text-secondary);
  margin: 0 0 var(--space-2xl) 0;
  font-weight: 400;
  line-height: 1.55;
}

/* ============================================
   LINKS
   ============================================ */

a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease;
}

a:hover {
  border-bottom-color: var(--text-secondary);
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  background: transparent;
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-full);
  text-decoration: none;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
  letter-spacing: -0.005em;
}

.btn:hover {
  background: var(--bg-secondary);
  border-color: var(--text-secondary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.btn-primary {
  background: var(--text-primary);
  color: var(--bg-primary);
  border-color: var(--text-primary);
}

.btn-primary:hover {
  background: #2a2a2a;
  border-color: #2a2a2a;
  color: var(--bg-primary);
}

/* ============================================
   PROFILE SECTION
   ============================================ */

.profile-section {
  display: flex;
  align-items: flex-start;
  gap: var(--space-lg);
  margin: var(--space-2xl) 0 var(--space-3xl) 0;
  padding: var(--space-xl);
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
}

.profile-image {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  box-shadow: var(--shadow-sm);
}

.profile-info {
  flex: 1;
  padding-top: 2px;
}

.profile-info p {
  margin: 0 0 var(--space-md) 0;
  font-size: 15px;
  line-height: 1.65;
}

.profile-info p:last-child {
  margin-bottom: 0;
}

/* ============================================
   DIVIDER
   ============================================ */

.divider {
  height: 1px;
  background: var(--border-subtle);
  margin: var(--space-3xl) 0;
  border: none;
}

/* ============================================
   PUBLICATION ITEMS
   ============================================ */

.publication-item {
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--border-subtle);
  transition: all 0.2s ease;
}

.publication-item:hover {
  padding-left: var(--space-md);
  margin-left: calc(-1 * var(--space-md));
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  border-bottom-color: transparent;
}

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

.publication-title {
  font-weight: 600;
  font-size: 16px;
  margin-bottom: var(--space-sm);
  line-height: 1.5;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.publication-meta {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   LISTS
   ============================================ */

ul, ol {
  margin: var(--space-lg) 0;
  padding-left: var(--space-xl);
}

li {
  margin: var(--space-md) 0;
  padding-left: var(--space-xs);
  line-height: 1.65;
  color: var(--text-primary);
  font-size: 15px;
}

li::marker {
  color: var(--text-tertiary);
}

/* Checklist */
.checklist {
  list-style: none;
  padding-left: 0;
  margin: var(--space-lg) 0;
}

.checklist li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  padding: 6px 0;
  margin: 6px 0;
  transition: all 0.15s ease;
}

.checklist li:hover {
  padding-left: var(--space-sm);
}

.checklist .check {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  margin-top: 2px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  line-height: 1;
  font-weight: 600;
}

.checklist .done {
  color: var(--text-tertiary);
}

.checklist .done + span {
  color: var(--text-tertiary);
  text-decoration: line-through;
  text-decoration-thickness: 1px;
}

.checklist .progress {
  color: var(--text-secondary);
}

.checklist .todo {
  color: var(--text-tertiary);
}

/* ============================================
   BLOCKQUOTE
   ============================================ */

blockquote {
  margin: var(--space-3xl) 0;
  padding: var(--space-lg) var(--space-xl);
  border-left: 2px solid var(--border-medium);
  background: var(--bg-secondary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

blockquote p {
  margin: 0;
  color: var(--text-secondary);
  font-style: italic;
  font-size: 15px;
  line-height: 1.65;
}

/* ============================================
   STATUS
   ============================================ */

.status {
  display: inline-block;
  font-size: 13px;
  color: var(--text-tertiary);
  margin-left: var(--space-xs);
}

/* ============================================
   PAGE HEADER
   ============================================ */

.page-header {
  margin-bottom: var(--space-2xl);
}

.page-header h1 {
  margin-bottom: var(--space-sm);
}

.page-header .subtitle {
  margin-bottom: 0;
}

/* ============================================
   THOUGHT PIECE / BLOG POST
   ============================================ */

.thought-piece {
  max-width: 680px;
  margin: 0 auto;
}

.thought-piece h2 {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.2;
  margin: 0 0 var(--space-md) 0;
  letter-spacing: -0.03em;
}

.thought-piece .date {
  font-size: 14px;
  color: var(--text-tertiary);
  margin: 0 0 var(--space-3xl) 0;
  font-weight: 500;
  letter-spacing: -0.005em;
}

.thought-piece p {
  font-size: 17px;
  line-height: 1.7;
  margin: 0 0 var(--space-xl) 0;
  color: var(--text-primary);
}

/* ============================================
   THOUGHT LIST (INDEX)
   ============================================ */

.thought-list {
  margin: var(--space-2xl) 0;
}

.thought-item {
  display: flex;
  align-items: baseline;
  gap: var(--space-md);
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--border-subtle);
  text-decoration: none;
  color: var(--text-primary);
  transition: all 0.2s ease;
}

.thought-item:hover {
  padding-left: var(--space-md);
  margin-left: calc(-1 * var(--space-md));
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  border-bottom-color: transparent;
}

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

.thought-date {
  font-size: 14px;
  color: var(--text-tertiary);
  font-weight: 500;
  letter-spacing: -0.005em;
  white-space: nowrap;
}

.thought-separator {
  color: var(--text-tertiary);
  font-weight: 400;
}

.thought-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

/* ============================================
   PAPER LIST
   ============================================ */

.paper-list {
  margin: var(--space-lg) 0;
}

.paper-item {
  display: flex;
  align-items: baseline;
  gap: var(--space-md);
  padding: 3px 0;
  text-decoration: none;
  color: var(--text-primary);
  transition: all 0.15s ease;
  border-bottom: none !important;
}

.paper-item:hover {
  border-bottom: none !important;
}

.paper-item:hover .paper-title {
  color: var(--text-secondary);
  cursor: pointer;
}

.paper-date {
  font-size: 14px;
  color: var(--text-tertiary);
  font-weight: 500;
  letter-spacing: -0.005em;
  white-space: nowrap;
  min-width: 130px;
}

.paper-separator {
  color: var(--text-tertiary);
  font-weight: 400;
}

.paper-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

/* ============================================
   PAPER ARTICLE
   ============================================ */

.paper-article {
  max-width: 720px;
  margin: 0 auto;
}

.paper-article h1 {
  font-size: 36px;
  font-weight: 700;
  line-height: 1.2;
  margin: 0 0 var(--space-md) 0;
  letter-spacing: -0.03em;
}

.paper-article h2 {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.3;
  margin: var(--space-xl) 0 var(--space-lg) 0;
  letter-spacing: -0.025em;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
}

.paper-article h2:first-of-type {
  border-top: none;
  padding-top: 0;
}

.paper-article h3 {
  font-size: 19px;
  font-weight: 600;
  line-height: 1.4;
  margin: var(--space-2xl) 0 var(--space-lg) 0;
  color: var(--text-primary);
  letter-spacing: -0.015em;
}

.paper-article .date {
  font-size: 14px;
  color: var(--text-tertiary);
  margin: 0 0 var(--space-3xl) 0;
  font-weight: 500;
  letter-spacing: -0.005em;
}

.paper-article p {
  font-size: 17px;
  line-height: 1.7;
  margin: 0 0 var(--space-lg) 0;
  color: var(--text-primary);
}

.paper-article ul,
.paper-article ol {
  margin: var(--space-lg) 0;
  padding-left: var(--space-xl);
}

.paper-article li {
  margin: var(--space-sm) 0;
  padding-left: 0;
  line-height: 1.7;
  color: var(--text-primary);
  font-size: 17px;
}

.paper-article strong {
  font-weight: 600;
  color: var(--text-primary);
}

.paper-article code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--bg-secondary);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
}

.paper-article pre {
  background: var(--bg-secondary) !important;
  color: var(--text-primary) !important;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
}

/* Math equations */
.equation {
  margin: var(--space-xl) 0;
  padding: var(--space-lg) 0;
  text-align: center;
  overflow-x: auto;
}

.paper-article .MathJax {
  font-size: 1.1em !important;
}

/* Comparison table */
.comparison-table {
  margin: var(--space-2xl) 0;
  overflow-x: auto;
}

.comparison-table table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}

.comparison-table th {
  background: var(--bg-secondary);
  padding: var(--space-md) var(--space-lg);
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--border-medium);
  color: var(--text-primary);
}

.comparison-table td {
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-primary);
  line-height: 1.6;
}

.comparison-table tr:last-child td {
  border-bottom: none;
}

.comparison-table tr:hover {
  background: var(--bg-hover);
}

/* ============================================
   DARK MODE TOGGLE
   ============================================ */

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  padding: 0;
  margin: 0 8px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-secondary);
  transition: color 0.15s ease;
}

.theme-toggle:hover {
  color: var(--text-primary);
}

.theme-toggle svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.theme-icon {
  display: none;
}

[data-theme="light"] .sun-icon,
[data-theme="dark"] .moon-icon {
  display: block;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media screen and (max-width: 768px) {
  .content {
    padding: var(--space-2xl) var(--space-md) var(--space-3xl);
  }

  h1 {
    font-size: 32px;
  }

  h2 {
    font-size: 22px;
  }

  h3 {
    font-size: 17px;
  }

  .subtitle {
    font-size: 16px;
  }

  .profile-section {
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: var(--space-lg);
  }

  .profile-image {
    width: 72px;
    height: 72px;
  }

  .nav-container {
    height: 52px;
    padding: 0 var(--space-md);
  }

  .nav-logo {
    font-size: 14px;
    gap: var(--space-sm);
  }

  .nav-logo svg {
    width: 20px;
    height: 20px;
  }

  .navbar a:not(.nav-logo) {
    padding: 6px 0;
    margin: 0 8px;
    font-size: 13px;
  }

  .icon-link {
    padding: 6px !important;
    margin: 0 6px !important;
  }

  .icon-link svg {
    width: 14px;
    height: 14px;
  }
}

@media screen and (max-width: 480px) {
  h1 {
    font-size: 28px;
  }

  h2 {
    font-size: 20px;
  }

  .nav-links {
    gap: 0;
  }

  .navbar a:not(.nav-logo) {
    padding: 5px 0;
    margin: 0 6px;
    font-size: 12px;
  }

  .icon-link {
    padding: 5px !important;
    margin: 0 4px !important;
  }
}

/* ============================================
   ACCESSIBILITY
   ============================================ */

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

  html {
    scroll-behavior: auto;
  }
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--text-primary);
  outline-offset: 2px;
}