/* ==========================================================================
   squaresphere — Design System
   A minimal, dark personal site inspired by mitchellh.com
   ========================================================================== */

/* ---------- CSS Custom Properties ---------- */
:root {
  /* Colors — dark palette */
  --color-bg: #1e1e21;
  --color-bg-subtle: #242428;
  --color-surface: #2a2a2f;
  --color-border: #38383e;
  --color-border-hover: #48484f;

  /* Text */
  --color-text: #e4e4e7;
  --color-text-secondary: #c8c8cf;
  --color-text-muted: #96969f;

  /* Accent */
  --color-accent: #a78bfa;
  --color-accent-hover: #c4b5fd;
  --color-accent-dim: rgba(167, 139, 250, 0.12);

  /* Links */
  --color-link: #a78bfa;
  --color-link-hover: #c4b5fd;
  --color-link-underline: rgba(167, 139, 250, 0.35);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;

  /* Font sizes — modular scale */
  --text-xs: 0.75rem;
  /* 12px */
  --text-sm: 0.8125rem;
  /* 13px */
  --text-base: 0.9375rem;
  /* 15px */
  --text-md: 1rem;
  /* 16px */
  --text-lg: 1.125rem;
  /* 18px */
  --text-xl: 1.25rem;
  /* 20px */
  --text-2xl: 1.5rem;
  /* 24px */
  --text-3xl: 1.875rem;
  /* 30px */

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Layout */
  --content-width: 640px;
  --site-padding: 1.5rem;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
}


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

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);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='80' height='80' viewBox='0 0 80 80'%3E%3Cg fill='none' stroke='%23ffffff' stroke-width='0.5' opacity='0.04'%3E%3C!-- Asanoha (hemp leaf) pattern --%3E%3Cline x1='40' y1='0' x2='40' y2='40'/%3E%3Cline x1='0' y1='40' x2='40' y2='40'/%3E%3Cline x1='80' y1='40' x2='40' y2='40'/%3E%3Cline x1='40' y1='80' x2='40' y2='40'/%3E%3Cline x1='0' y1='0' x2='40' y2='40'/%3E%3Cline x1='80' y1='0' x2='40' y2='40'/%3E%3Cline x1='0' y1='80' x2='40' y2='40'/%3E%3Cline x1='80' y1='80' x2='40' y2='40'/%3E%3Cline x1='20' y1='0' x2='0' y2='20'/%3E%3Cline x1='60' y1='0' x2='80' y2='20'/%3E%3Cline x1='20' y1='80' x2='0' y2='60'/%3E%3Cline x1='60' y1='80' x2='80' y2='60'/%3E%3Cline x1='0' y1='20' x2='0' y2='60'/%3E%3Cline x1='80' y1='20' x2='80' y2='60'/%3E%3Cline x1='20' y1='0' x2='60' y2='0'/%3E%3Cline x1='20' y1='80' x2='60' y2='80'/%3E%3C/g%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 80px 80px;
  min-height: 100vh;
}

::selection {
  background-color: var(--color-accent-dim);
  color: var(--color-accent-hover);
}

a {
  color: var(--color-link);
  text-decoration: none;
  text-underline-offset: 3px;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-link-hover);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}


/* ---------- Site Wrapper ---------- */
.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 var(--site-padding);
}


/* ---------- Header / Navigation ---------- */
.site-header {
  padding-top: var(--space-2xl);
  padding-bottom: var(--space-3xl);
  opacity: 0;
  animation: fadeInDown 600ms var(--transition-base) forwards;
  animation-delay: 100ms;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-text);
  text-decoration: none;
  font-weight: 600;
  font-size: var(--text-md);
  letter-spacing: -0.01em;
  transition: color var(--transition-fast);
}

.nav-brand:hover {
  color: var(--color-accent);
}

.nav-brand-icon {
  display: inline-block;
  vertical-align: middle;
  position: relative;
  top: 2px;
  flex-shrink: 0;
  transition: transform var(--transition-base), filter var(--transition-base);
}

.nav-brand-text {
  vertical-align: middle;
}

.nav-brand:hover .nav-brand-icon {
  transform: scale(1.08);
  filter: drop-shadow(0 0 6px var(--color-accent));
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-link {
  color: var(--color-text-muted);
  font-size: var(--text-base);
  font-weight: 500;
  text-decoration: none;
  position: relative;
  padding: var(--space-xs) 0;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

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

.nav-link:hover::after {
  transform: scaleX(1);
}

.nav-link.active {
  color: var(--color-text);
}

.nav-link.active::after {
  transform: scaleX(1);
  background-color: var(--color-accent-dim);
  background-color: var(--color-accent);
  opacity: 0.5;
}


/* ---------- Main Content ---------- */
.main-content {
  flex: 1;
  opacity: 0;
  animation: fadeIn 600ms ease forwards;
  animation-delay: 250ms;
}


/* ---------- About / Homepage ---------- */
.about-section {
  max-width: 100%;
}

.about-name {
  font-size: var(--text-3xl);
  font-weight: 600;
  letter-spacing: -0.035em;
  line-height: 1.2;
  color: var(--color-text);
  margin-bottom: var(--space-2xl);
  position: relative;
}

.about-name::after {
  content: '';
  display: block;
  width: 40px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), transparent);
  margin-top: var(--space-lg);
  border-radius: 1px;
}

.about-bio {
  max-width: 100%;
}

.about-bio p {
  color: var(--color-text-secondary);
  font-size: var(--text-base);
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.about-bio p:last-child {
  margin-bottom: 0;
}

.about-bio a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-color: var(--color-link-underline);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: all var(--transition-fast);
}

.about-bio a:hover {
  color: var(--color-link-hover);
  text-decoration-color: var(--color-link-hover);
}


/* ---------- Page Title ---------- */
.page-title {
  font-size: var(--text-2xl);
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--color-text);
  margin-bottom: var(--space-2xl);
  position: relative;
}

.page-title::after {
  content: '';
  display: block;
  width: 30px;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), transparent);
  margin-top: var(--space-md);
  border-radius: 1px;
}


/* ---------- Writing / Post List ---------- */
.post-list {
  display: flex;
  flex-direction: column;
}

.post-item {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-lg);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
  transition: all var(--transition-fast);
  position: relative;
}

.post-item:first-child {
  border-top: 1px solid var(--color-border);
}

.post-item::before {
  content: '';
  position: absolute;
  left: calc(-1 * var(--space-md));
  right: calc(-1 * var(--space-md));
  top: 0;
  bottom: 0;
  background-color: var(--color-accent-dim);
  border-radius: var(--radius-md);
  opacity: 0;
  transition: opacity var(--transition-fast);
  pointer-events: none;
}

.post-item:hover::before {
  opacity: 1;
}

.post-item:hover {
  border-bottom-color: transparent;
}

.post-item:hover+.post-item {
  border-top-color: transparent;
}

.post-title {
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text);
  transition: color var(--transition-fast);
  position: relative;
  z-index: 1;
}

.post-item:hover .post-title {
  color: var(--color-accent-hover);
}

.post-date {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  white-space: nowrap;
  flex-shrink: 0;
  font-variant-numeric: tabular-nums;
  position: relative;
  z-index: 1;
}


/* ---------- Misc List ---------- */
.misc-list {
  list-style: none;
  padding: 0;
}

.misc-list li {
  padding: var(--space-sm) 0;
}

.misc-link {
  color: var(--color-text-secondary);
  font-size: var(--text-base);
  text-decoration: underline;
  text-decoration-color: var(--color-link-underline);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: all var(--transition-fast);
}

.misc-link:hover {
  color: var(--color-link-hover);
  text-decoration-color: var(--color-link-hover);
}


/* ---------- Bookshelf ---------- */
.bookshelf-intro {
  color: var(--color-text-muted);
  font-size: var(--text-base);
  margin-bottom: var(--space-2xl);
  font-style: italic;
}

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

.shelf-books {
  display: flex;
  align-items: flex-end;
  gap: 3px;
  padding: 0 var(--space-sm);
  min-height: 220px;
}

.book {
  display: flex;
  align-items: stretch;
  width: var(--book-width, 36px);
  height: var(--book-height, 200px);
  background: linear-gradient(135deg,
      hsl(var(--book-hue, 270) 25% 22%),
      hsl(var(--book-hue, 270) 20% 18%));
  border-radius: 2px 4px 4px 2px;
  position: relative;
  cursor: pointer;
  text-decoration: none;
  transition: transform var(--transition-base),
    box-shadow var(--transition-base),
    filter var(--transition-base);
  transform-origin: bottom center;
  /* Spine edge highlight */
  border-left: 2px solid hsl(var(--book-hue, 270) 20% 28%);
  border-right: 1px solid hsl(var(--book-hue, 270) 15% 12%);
  /* Subtle texture */
  box-shadow: inset -1px 0 2px rgba(0, 0, 0, 0.3),
    inset 1px 0 1px rgba(255, 255, 255, 0.03);
}

.book::before {
  content: '';
  position: absolute;
  top: 6px;
  bottom: 6px;
  left: 3px;
  width: 1px;
  background: linear-gradient(to bottom,
      transparent,
      hsl(var(--book-hue, 270) 30% 35%) 20%,
      hsl(var(--book-hue, 270) 30% 35%) 80%,
      transparent);
  opacity: 0.5;
}

.book::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 6px;
  background: linear-gradient(to right,
      transparent,
      rgba(0, 0, 0, 0.15));
  border-radius: 0 4px 4px 0;
}

.book:hover {
  transform: translateY(-12px);
  box-shadow: inset -1px 0 2px rgba(0, 0, 0, 0.3),
    inset 1px 0 1px rgba(255, 255, 255, 0.03),
    0 12px 24px rgba(0, 0, 0, 0.4),
    0 0 20px hsla(var(--book-hue, 270), 40%, 50%, 0.15);
  filter: brightness(1.15);
  z-index: 2;
}

.book-spine {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  padding: 12px 0;
  gap: 8px;
  overflow: hidden;
}

.book-title {
  font-size: 0.6rem;
  font-weight: 600;
  color: hsl(var(--book-hue, 270) 15% 70%);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
  max-height: 70%;
  transition: color var(--transition-fast);
}

.book:hover .book-title {
  color: hsl(var(--book-hue, 270) 30% 85%);
}

.book-author {
  font-size: 0.5rem;
  font-weight: 400;
  color: hsl(var(--book-hue, 270) 10% 45%);
  letter-spacing: 0.04em;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

.book:hover .book-author {
  color: hsl(var(--book-hue, 270) 15% 60%);
}

/* Shelf surface */
.shelf-edge {
  height: 8px;
  background: linear-gradient(to bottom,
      var(--color-border-hover),
      var(--color-border));
  border-radius: 0 0 2px 2px;
  position: relative;
}

.shelf-shadow {
  position: absolute;
  top: 8px;
  left: 0;
  right: 0;
  height: 20px;
  background: linear-gradient(to bottom,
      rgba(0, 0, 0, 0.25),
      transparent);
  pointer-events: none;
}


/* ---------- Article / Blog Post ---------- */
.article {
  max-width: 100%;
}

.article-header {
  margin-bottom: var(--space-2xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid var(--color-border);
}

.article-title {
  font-size: var(--text-3xl);
  font-weight: 600;
  letter-spacing: -0.035em;
  line-height: 1.2;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
}

.article-date {
  display: block;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-md);
  font-variant-numeric: tabular-nums;
}

.article-body {
  color: var(--color-text-secondary);
  font-size: var(--text-base);
  line-height: 1.8;
}

.article-body p {
  margin-bottom: var(--space-lg);
}

.article-body h2 {
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.article-body h3 {
  font-size: var(--text-lg);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--color-text);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.article-body a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-color: var(--color-link-underline);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: all var(--transition-fast);
}

.article-body a:hover {
  color: var(--color-link-hover);
  text-decoration-color: var(--color-link-hover);
}

.article-body em {
  font-style: italic;
  color: var(--color-text);
}

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

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

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

.article-body blockquote {
  border-left: 2px solid var(--color-accent);
  padding-left: var(--space-lg);
  margin: var(--space-xl) 0;
  color: var(--color-text-muted);
  font-style: italic;
}

/* Code blocks */
.article-body pre {
  background-color: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin: var(--space-xl) 0;
  overflow-x: auto;
  font-size: var(--text-sm);
  line-height: 1.6;
  -webkit-overflow-scrolling: touch;
}

.article-body pre code {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  background: none;
  padding: 0;
  border-radius: 0;
  border: none;
}

.article-body code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  color: var(--color-accent);
  background-color: var(--color-accent-dim);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(167, 139, 250, 0.1);
}

/* Horizontal rule */
.article-body hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: var(--space-2xl) 0;
}



/* ---------- Contact Form ---------- */
.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
  max-width: 100%;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.form-label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.02em;
}

.form-input,
.form-textarea {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  outline: none;
  transition: border-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-text-muted);
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px var(--color-accent-dim);
}

.form-textarea {
  resize: vertical;
  min-height: 160px;
  line-height: 1.7;
}

.form-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  align-self: flex-start;
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-bg);
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-hover));
  border: none;
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-xl);
  cursor: pointer;
  transition: transform var(--transition-fast),
    box-shadow var(--transition-fast),
    opacity var(--transition-fast);
}

.form-button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(167, 139, 250, 0.3);
  opacity: 0.92;
}

.form-button:active {
  transform: translateY(0);
  box-shadow: none;
}

.form-button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.form-status {
  font-size: var(--text-sm);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  display: none;
}

.form-status--success,
.form-status--error {
  display: block;
}

.form-status--success {
  color: #a3e635;
  background-color: rgba(163, 230, 53, 0.08);
  border: 1px solid rgba(163, 230, 53, 0.2);
}

.form-status--error {
  color: #fb7185;
  background-color: rgba(251, 113, 133, 0.08);
  border: 1px solid rgba(251, 113, 133, 0.2);
}


/* ---------- Footer ---------- */
.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3xl) 0 var(--space-2xl);
  margin-top: var(--space-3xl);
  opacity: 0;
  animation: fadeIn 600ms ease forwards;
  animation-delay: 400ms;
}

.social-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.social-link:hover {
  color: var(--color-text);
  background-color: var(--color-surface);
  transform: translateY(-1px);
}

.social-link svg {
  flex-shrink: 0;
}

.footer-copyright {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.04em;
}


/* ---------- Animations ---------- */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}


/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background-color: var(--color-border);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background-color: var(--color-border-hover);
}


/* ---------- Responsive ---------- */
@media (max-width: 600px) {
  :root {
    --site-padding: 1.25rem;
  }

  .site-header {
    padding-top: var(--space-xl);
    padding-bottom: var(--space-2xl);
  }

  .nav {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-md);
  }

  .nav-links {
    gap: var(--space-md);
  }

  .about-name {
    font-size: var(--text-2xl);
  }

  .article-title {
    font-size: var(--text-2xl);
  }

  .post-item {
    flex-direction: column;
    gap: var(--space-xs);
  }

  .post-date {
    font-size: var(--text-xs);
  }

  .social-links {
    gap: var(--space-md);
  }

  .site-footer {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-md);
  }

  .shelf-books {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding-bottom: var(--space-sm);
  }
}

@media (max-width: 400px) {
  :root {
    --site-padding: 1rem;
  }

  .about-name {
    font-size: var(--text-xl);
  }

  .article-title {
    font-size: var(--text-xl);
  }
}


/* ---------- Reduced Motion ---------- */
@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;
  }
}