/* ==========================================================================
   Design Tokens
   ========================================================================== */

:root {
  /* Type Scale */
  --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);

  /* Spacing */
  --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;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Fonts */
  --font-body: 'Satoshi', 'Helvetica Neue', sans-serif;
  --font-display: 'General Sans', 'Helvetica Neue', sans-serif;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;

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

  /* Content widths */
  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;
}

/* ==========================================================================
   Light Mode (Default)
   ========================================================================== */

:root,
[data-theme='light'] {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-surface-alt: #f4f4f5;
  --color-border: #e4e4e7;
  --color-divider: #ebebed;
  --color-text: #18181b;
  --color-text-muted: #71717a;
  --color-text-faint: #a1a1aa;
  --color-primary: #1a5c6b;
  --color-primary-hover: #134a56;
  --color-primary-surface: #e8f4f6;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
}

/* ==========================================================================
   Dark Mode
   ========================================================================== */

[data-theme='dark'] {
  --color-bg: #121214;
  --color-surface: #1c1c1f;
  --color-surface-alt: #232326;
  --color-border: #2e2e32;
  --color-divider: #27272a;
  --color-text: #e4e4e7;
  --color-text-muted: #a1a1aa;
  --color-text-faint: #63636b;
  --color-primary: #5bb8c9;
  --color-primary-hover: #7ccbd8;
  --color-primary-surface: #1a2c30;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #121214;
    --color-surface: #1c1c1f;
    --color-surface-alt: #232326;
    --color-border: #2e2e32;
    --color-divider: #27272a;
    --color-text: #e4e4e7;
    --color-text-muted: #a1a1aa;
    --color-text-faint: #63636b;
    --color-primary: #5bb8c9;
    --color-primary-hover: #7ccbd8;
    --color-primary-surface: #1a2c30;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  }
}

/* ==========================================================================
   Base Reset
   ========================================================================== */

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

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  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-color: var(--color-bg);
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

ul[role='list'],
ol[role='list'] {
  list-style: none;
}

input, button, textarea, select {
  font: inherit;
  color: inherit;
}

h1, h2, h3, h4, h5, h6 {
  text-wrap: balance;
  line-height: 1.2;
}

p, li, figcaption {
  text-wrap: pretty;
  max-width: 72ch;
}

::selection {
  background: rgba(26, 92, 107, 0.15);
  color: var(--color-text);
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

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);
}

button {
  cursor: pointer;
  background: none;
  border: none;
}

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

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

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

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

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

.section {
  padding-block: clamp(var(--space-12), 8vw, var(--space-24));
}

.section-alt {
  background-color: var(--color-surface-alt);
}

/* ==========================================================================
   Header
   ========================================================================== */

.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--color-bg) 85%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-divider);
}

.header-inner {
  max-width: var(--content-default);
  margin-inline: auto;
  padding-inline: var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 3.5rem;
}

.logo {
  color: var(--color-text);
  display: flex;
  align-items: center;
}

.logo:hover {
  color: var(--color-primary);
}

.nav-list {
  display: flex;
  gap: var(--space-6);
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  letter-spacing: 0.01em;
}

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

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
}

.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-surface-alt);
}

/* ==========================================================================
   Hero
   ========================================================================== */

.hero {
  padding-block: clamp(var(--space-16), 12vw, var(--space-32)) clamp(var(--space-12), 8vw, var(--space-24));
}

.hero-layout {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.hero-avatar {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  border: 3px solid var(--color-border);
}

.hero-name {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-3);
}

.hero-title {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  font-weight: 400;
  margin-bottom: var(--space-2);
}

.hero-fields {
  font-size: var(--text-sm);
  color: var(--color-text-faint);
  font-weight: 400;
  letter-spacing: 0.02em;
}

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

.section-heading {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-6);
}

.section-subtext {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-8);
  max-width: 60ch;
}

.about-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.about-content p {
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ==========================================================================
   Publications
   ========================================================================== */

.pub-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  counter-reset: none;
}

.pub-item {
  display: grid;
  grid-template-columns: 3.5rem 1fr;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--color-divider);
}

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

.pub-year {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-faint);
  padding-top: 0.125rem;
  font-variant-numeric: tabular-nums;
}

.pub-details {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.pub-title {
  font-weight: 500;
  line-height: 1.4;
  font-size: var(--text-base);
}

.pub-authors {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.5;
}

.pub-journal {
  font-size: var(--text-sm);
  color: var(--color-text-faint);
  font-style: italic;
}

.pub-citations {
  font-size: var(--text-xs);
  color: var(--color-primary);
  font-weight: 500;
}

/* ==========================================================================
   Contact / Consultation
   ========================================================================== */

.contact-form {
  max-width: 32rem;
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text);
}

.optional {
  font-weight: 400;
  color: var(--color-text-faint);
}

.form-input {
  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-base);
  color: var(--color-text);
  width: 100%;
}

.form-input::placeholder {
  color: var(--color-text-faint);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26, 92, 107, 0.1);
}

.form-textarea {
  resize: vertical;
  min-height: 7rem;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-6);
  background: var(--color-primary);
  color: #fff;
  font-size: var(--text-sm);
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  align-self: flex-start;
  letter-spacing: 0.01em;
}

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

/* ==========================================================================
   Footer
   ========================================================================== */

.footer {
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-8);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer-text {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

.footer-links {
  display: flex;
  gap: var(--space-6);
}

.footer-link {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-decoration: none;
}

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

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

@media (max-width: 640px) {
  .header-inner {
    height: 3rem;
  }

  .nav-list {
    gap: var(--space-4);
  }

  .nav-link {
    font-size: var(--text-xs);
  }

  .hero {
    padding-block: clamp(var(--space-12), 10vw, var(--space-20)) var(--space-10);
  }

  .hero-layout {
    flex-direction: column;
    text-align: center;
  }

  .hero-avatar {
    width: 120px;
    height: 120px;
  }

  .hero-fields {
    margin-inline: auto;
  }

  .pub-item {
    grid-template-columns: 1fr;
    gap: var(--space-1);
  }

  .pub-year {
    font-size: var(--text-xs);
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .contact-form {
    max-width: 100%;
  }
}