/* ==========================================================================
   BILAL NASEER, MD — Design System
   Editorial physician site. Warm ivory + deep clinical navy.
   Typography: Instrument Serif (display) + Inter (body) — matches print card.
   ========================================================================== */

:root, [data-theme='light'] {
  /* Surfaces — warm ivory, matches business card stock */
  --color-bg: #f7f4ee;
  --color-surface: #fbf8f2;
  --color-surface-2: #f2ede4;
  --color-surface-offset: #eae4d8;
  --color-border: #d9d0bf;
  --color-divider: #e5ddce;

  /* Text — deep near-black with warm undertone */
  --color-text: #1c1a15;
  --color-text-muted: #5f5a4e;
  --color-text-faint: #9a9484;

  /* Accent — deep clinical navy, matches card ink */
  --color-primary: #1c375c;
  --color-primary-hover: #10233f;
  --color-primary-active: #081729;
  --color-primary-highlight: #dce1eb;

  /* Radius */
  --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);

  --shadow-sm: 0 1px 2px oklch(0.2 0.01 80 / 0.06);
  --shadow-md: 0 4px 12px oklch(0.2 0.01 80 / 0.08);
  --shadow-lg: 0 12px 32px oklch(0.2 0.01 80 / 0.14);

  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;

  /* Fonts */
  --font-display: 'Instrument Serif', Georgia, 'Times New Roman', serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', sans-serif;

  /* 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);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 5rem);
  --text-hero: clamp(3rem, 0.5rem + 7vw, 7rem);

  /* 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;
}

[data-theme='dark'] {
  --color-bg: #141311;
  --color-surface: #1a1815;
  --color-surface-2: #201d1a;
  --color-surface-offset: #26221e;
  --color-border: #3a352d;
  --color-divider: #2a2621;

  --color-text: #e8e2d2;
  --color-text-muted: #93897a;
  --color-text-faint: #5f584d;

  --color-primary: #7fa8d8;
  --color-primary-hover: #a4c1e4;
  --color-primary-active: #c2d5eb;
  --color-primary-highlight: #29334a;

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

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #141311;
    --color-surface: #1a1815;
    --color-surface-2: #201d1a;
    --color-surface-offset: #26221e;
    --color-border: #3a352d;
    --color-divider: #2a2621;
    --color-text: #e8e2d2;
    --color-text-muted: #93897a;
    --color-text-faint: #5f584d;
    --color-primary: #7fa8d8;
    --color-primary-hover: #a4c1e4;
    --color-primary-active: #c2d5eb;
    --color-primary-highlight: #29334a;
  }
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-interactive);
}

.site-header--scrolled {
  border-bottom-color: var(--color-divider);
}

.site-header__inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding: var(--space-4) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}

.site-brand {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.site-brand em {
  font-style: normal;
  color: var(--color-text-muted);
  font-size: 0.85em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.site-nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.site-nav__list {
  display: none;
  gap: var(--space-6);
  list-style: none;
}

@media (min-width: 768px) {
  .site-nav__list { display: flex; }
}

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

.site-nav__list a:hover {
  color: var(--color-text);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}

.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-surface-2);
}

.menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}

.menu-toggle:hover,
.menu-toggle:active {
  color: var(--color-text);
  background: var(--color-surface-2);
}

.menu-toggle__icon {
  position: relative;
  width: 20px;
  height: 16px;
}

.menu-toggle__icon span {
  position: absolute;
  left: 0;
  width: 20px;
  height: 1.5px;
  border-radius: var(--radius-full);
  background: currentColor;
  transform-origin: center;
  transition:
    top var(--transition-interactive),
    opacity var(--transition-interactive),
    transform var(--transition-interactive);
}

.menu-toggle__icon span:nth-child(1) { top: 1px; }
.menu-toggle__icon span:nth-child(2) { top: 7px; }
.menu-toggle__icon span:nth-child(3) { top: 13px; }

.menu-toggle[aria-expanded="true"] .menu-toggle__icon span:nth-child(1) {
  top: 7px;
  transform: rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__icon span:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] .menu-toggle__icon span:nth-child(3) {
  top: 7px;
  transform: rotate(-45deg);
}

.mobile-menu {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  visibility: hidden;
  opacity: 0;
  pointer-events: none;
  transform: translateY(-8px);
  background: var(--color-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-top: 1px solid var(--color-divider);
  border-bottom: 1px solid var(--color-divider);
  box-shadow: 0 14px 32px oklch(0.2 0.02 75 / 0.12);
  transition:
    opacity var(--transition-interactive),
    transform var(--transition-interactive),
    visibility var(--transition-interactive);
}

.menu-is-open .mobile-menu {
  visibility: visible;
  opacity: 1;
  pointer-events: auto;
  transform: none;
}

.mobile-menu__inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding: var(--space-3) var(--space-6) var(--space-5);
  display: grid;
}

.mobile-menu__inner a {
  min-height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--color-divider);
  color: var(--color-text);
  text-decoration: none;
  font-family: var(--font-display);
  font-size: var(--text-lg);
  letter-spacing: -0.005em;
}

.mobile-menu__inner a::after {
  content: "↘";
  color: var(--color-primary);
  font-family: var(--font-body);
  font-size: var(--text-sm);
}

.mobile-menu__inner a:last-child {
  border-bottom: 0;
}

.mobile-menu__inner a:active {
  color: var(--color-primary);
}

@media (min-width: 768px) {
  .menu-toggle,
  .mobile-menu {
    display: none;
  }
}

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

.container {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding-inline: var(--space-6);
}

.container-narrow {
  max-width: var(--content-narrow);
  margin: 0 auto;
  padding-inline: var(--space-6);
}

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

.section--tight {
  padding-block: clamp(var(--space-10), 6vw, var(--space-20));
}

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

.hero {
  padding-block: clamp(var(--space-16), 12vw, var(--space-32)) clamp(var(--space-12), 8vw, var(--space-20));
}

.hero__grid {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding-inline: var(--space-6);
  display: grid;
  gap: clamp(var(--space-8), 6vw, var(--space-16));
  align-items: center;
  grid-template-columns: 1fr;
}

@media (min-width: 900px) {
  .hero__grid {
    grid-template-columns: 1.3fr 1fr;
  }
}

.hero__eyebrow {
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-6);
}

.hero__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: var(--text-hero);
  line-height: 0.95;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-6);
}

.hero__lede {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 34ch;
  margin-bottom: var(--space-8);
  line-height: 1.5;
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.hero__photo {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-surface-offset);
  aspect-ratio: 4 / 5;
  max-width: 420px;
  justify-self: center;
  width: 100%;
}

.hero__photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
}

/* ========================================================================== */
/* Buttons                                                                    */
/* ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.005em;
  border-radius: var(--radius-full);
  text-decoration: none;
  border: 1px solid transparent;
  line-height: 1;
}

.btn--primary {
  background: var(--color-primary);
  color: #f7f4ee;
}

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

.btn--ghost {
  color: var(--color-text);
  border-color: var(--color-border);
  background: transparent;
}

.btn--ghost:hover {
  background: var(--color-surface-2);
  border-color: var(--color-text-muted);
}

.btn svg {
  width: 16px; height: 16px;
}

/* ========================================================================== */
/* Section headings                                                           */
/* ========================================================================== */

.section-eyebrow {
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: var(--text-2xl);
  line-height: 1.05;
  letter-spacing: -0.015em;
  color: var(--color-text);
  margin-bottom: var(--space-8);
  max-width: 22ch;
}

.section-title--tight {
  margin-bottom: var(--space-6);
}

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

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

.about__grid {
  display: grid;
  gap: clamp(var(--space-8), 6vw, var(--space-16));
  grid-template-columns: 1fr;
}

@media (min-width: 900px) {
  .about__grid { grid-template-columns: 1fr 2fr; }
}

.about__prose p + p {
  margin-top: var(--space-4);
}

.about__prose {
  font-size: var(--text-base);
  color: var(--color-text);
  line-height: 1.7;
  max-width: 62ch;
}

.about__prose em {
  color: var(--color-primary);
  font-style: normal;
  font-weight: 500;
}

.credentials {
  list-style: none;
  border-top: 1px solid var(--color-divider);
  margin-top: var(--space-8);
  padding-top: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.credentials li {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-weight: 500;
  line-height: 1.5;
}

/* ========================================================================== */
/* Practice / Roles cards                                                     */
/* ========================================================================== */

.roles__grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}

@media (min-width: 700px) {
  .roles__grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1000px) {
  .roles__grid { grid-template-columns: repeat(3, 1fr); }
}

.role-card {
  padding: var(--space-6);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  display: flex;
  flex-direction: column;
}

.role-card__label {
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.role-card__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  line-height: 1.2;
  color: var(--color-text);
  margin-bottom: var(--space-2);
  font-weight: 400;
}

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

.role-card__meta {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  margin-top: var(--space-4);
  letter-spacing: 0.03em;
  text-transform: uppercase;
  font-weight: 500;
}

/* ========================================================================== */
/* Teaching / lectures list                                                   */
/* ========================================================================== */

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

.lecture-list {
  list-style: none;
  display: grid;
  gap: var(--space-6);
}

.lecture {
  padding-block: var(--space-6);
  border-top: 1px solid var(--color-divider);
  display: grid;
  gap: var(--space-2) var(--space-6);
  grid-template-columns: 1fr;
}

@media (min-width: 720px) {
  .lecture {
    grid-template-columns: 120px 1fr;
  }
}

.lecture__date {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.lecture__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  line-height: 1.25;
  color: var(--color-text);
  margin-bottom: var(--space-1);
  font-weight: 400;
}

.lecture__venue {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.lecture:last-child {
  border-bottom: 1px solid var(--color-divider);
}

/* ========================================================================== */
/* Leadership grid                                                            */
/* ========================================================================== */

.leadership__grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}

@media (min-width: 720px) {
  .leadership__grid { grid-template-columns: repeat(2, 1fr); }
}

.leadership-item {
  padding: var(--space-6) 0;
  border-top: 1px solid var(--color-divider);
}

.leadership-item__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  line-height: 1.25;
  color: var(--color-text);
  margin-bottom: var(--space-2);
  font-weight: 400;
}

.leadership-item__where {
  font-size: var(--text-xs);
  color: var(--color-primary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.leadership-item__desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.55;
}

/* ========================================================================== */
/* News / press feature                                                       */
/* ========================================================================== */

.press {
  background: var(--color-primary);
  color: color-mix(in oklab, #f7f4ee 96%, transparent);
}

.press .section-eyebrow {
  color: color-mix(in oklab, #f7f4ee 70%, transparent);
}

.press__quote {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: var(--text-xl);
  line-height: 1.3;
  letter-spacing: -0.005em;
  color: #f7f4ee;
  max-width: 40ch;
  margin-bottom: var(--space-8);
}

.press__quote::before {
  content: '“';
  display: block;
  font-size: 3em;
  line-height: 0.6;
  margin-bottom: var(--space-4);
  color: color-mix(in oklab, #f7f4ee 40%, transparent);
}

.press__attribution {
  font-size: var(--text-sm);
  color: color-mix(in oklab, #f7f4ee 75%, transparent);
  margin-bottom: var(--space-2);
}

.press__attribution a {
  color: #f7f4ee;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

.press__source {
  font-size: var(--text-xs);
  color: color-mix(in oklab, #f7f4ee 55%, transparent);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 500;
}

/* ========================================================================== */
/* Writing / clinical notes                                                   */
/* ========================================================================== */

.notes {
  background: var(--color-bg);
}

.notes__list {
  list-style: none;
  display: grid;
  gap: var(--space-6);
  max-width: var(--content-default);
  margin: 0 auto;
}

.note-card {
  display: block;
  padding: var(--space-8);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-text);
  text-decoration: none;
}

.note-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.note-card__meta {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 500;
  margin-bottom: var(--space-3);
}

.note-card__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: var(--text-xl);
  line-height: 1.15;
  color: var(--color-text);
  margin-bottom: var(--space-3);
  letter-spacing: -0.01em;
}

.note-card__dek {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  line-height: 1.55;
  max-width: 55ch;
}

/* ========================================================================== */
/* Research list                                                              */
/* ========================================================================== */

.research__list {
  list-style: none;
  display: grid;
  gap: var(--space-6);
}

.research-item {
  padding-block: var(--space-5);
  border-top: 1px solid var(--color-divider);
}

.research-item__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  line-height: 1.25;
  color: var(--color-text);
  margin-bottom: var(--space-1);
  font-weight: 400;
}

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

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

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

.contact__grid {
  display: grid;
  gap: var(--space-8);
  grid-template-columns: 1fr;
  align-items: end;
}

@media (min-width: 800px) {
  .contact__grid { grid-template-columns: 1.2fr 1fr; }
}

.contact__methods {
  list-style: none;
  display: grid;
  gap: var(--space-3);
  margin-bottom: var(--space-8);
}

.contact__methods a {
  color: var(--color-text);
  text-decoration: none;
  font-family: var(--font-display);
  font-size: var(--text-xl);
  line-height: 1.2;
  letter-spacing: -0.005em;
}

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

.contact__label {
  display: inline-block;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-weight: 600;
  margin-right: var(--space-3);
  min-width: 68px;
}

.contact__cta-block {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  background: var(--color-bg);
}

.contact__cta-block h3 {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--space-3);
  line-height: 1.3;
}

.contact__cta-block p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  line-height: 1.5;
}

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

.site-footer {
  padding-block: var(--space-12);
  border-top: 1px solid var(--color-divider);
  background: var(--color-bg);
}

.site-footer__inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding-inline: var(--space-6);
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
  align-items: baseline;
}

@media (min-width: 720px) {
  .site-footer__inner { grid-template-columns: 1fr auto; }
}

.site-footer__brand {
  font-family: var(--font-display);
  color: var(--color-text);
  font-size: var(--text-base);
}

.site-footer__meta {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-weight: 500;
}

/* ========================================================================== */
/* Scroll reveal                                                              */
/* ========================================================================== */

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 800ms cubic-bezier(0.16, 1, 0.3, 1), transform 800ms cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}