/*
 * João Gaspar — Aerospace Engineer Portfolio
 * styles.css
 * ==========================================
 * A clean, engineering-inspired stylesheet.
 * Designed for minimal visual weight, strong
 * readability, and professional precision.
 *
 * Structure:
 *  1.  CSS Custom Properties (Design Tokens)
 *  2.  Reset & Base
 *  3.  Reusable Components (buttons, labels)
 *  4.  Navigation
 *  5.  Hero Section
 *  6.  About / Profile Photo
 *  7.  Projects Grid
 *  8.  Engineering Toolbox
 *  9.  CV Section
 *  10. Footer / Contact
 *  11. Project Page (project.html)
 *  12. Scroll Animations
 *  13. Responsive — Tablet (≤900px)
 *  14. Responsive — Mobile (≤640px)
 */


/* ============================================================
   1. CSS Custom Properties
   ============================================================ */
:root {
  /* --- Color System --- */
  --clr-bg:            #f5f7fb;          /* page background  */
  --clr-surface:       #ffffff;          /* cards, panels    */
  --clr-surface-alt:   #edf1f7;          /* subtle fills     */
  --clr-border:        #dde3ed;          /* dividers, rings  */

  --clr-text-primary:   #18202e;         /* headings, labels */
  --clr-text-secondary: #485668;         /* body copy        */
  --clr-text-muted:     #8895a7;         /* meta, captions   */

  --clr-accent:         #2563a8;         /* engineering blue */
  --clr-accent-hover:   #1a4d90;
  --clr-accent-light:   #eaf2fb;         /* accent tint bg   */
  --clr-accent-subtle:  #c7ddf5;         /* accent border    */

  --clr-tag-bg:   #e6ecf5;
  --clr-tag-text: #2d4a70;

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

  /* --- Spacing Scale (4px base) --- */
  --sp-1:  0.25rem;    /*  4px */
  --sp-2:  0.5rem;     /*  8px */
  --sp-3:  0.75rem;    /* 12px */
  --sp-4:  1rem;       /* 16px */
  --sp-5:  1.25rem;    /* 20px */
  --sp-6:  1.5rem;     /* 24px */
  --sp-8:  2rem;       /* 32px */
  --sp-10: 2.5rem;     /* 40px */
  --sp-12: 3rem;       /* 48px */
  --sp-16: 4rem;       /* 64px */
  --sp-20: 5rem;       /* 80px */
  --sp-24: 6rem;       /* 96px */

  /* --- Border Radius --- */
  --r-sm:   4px;
  --r-md:   8px;
  --r-lg:   12px;
  --r-xl:   20px;
  --r-full: 9999px;

  /* --- Shadows (blue-tinted for cohesion) --- */
  --shadow-sm:   0 1px 3px rgba(20, 40, 80, 0.06),
                 0 1px 2px rgba(20, 40, 80, 0.04);
  --shadow-md:   0 3px 10px rgba(20, 40, 80, 0.09),
                 0 1px 3px rgba(20, 40, 80, 0.05);
  --shadow-lg:   0 8px 28px rgba(20, 40, 80, 0.11),
                 0 3px 8px  rgba(20, 40, 80, 0.06);

  /* --- Transitions --- */
  --t-fast: 140ms cubic-bezier(0.4, 0, 0.2, 1);
  --t-base: 240ms cubic-bezier(0.4, 0, 0.2, 1);
  --t-slow: 380ms cubic-bezier(0.4, 0, 0.2, 1);

  /* --- Layout --- */
  --max-w:      1120px;
  --max-w-text:  720px;
  --pad-x:      clamp(1rem, 5vw, 2rem);
  --nav-h:      64px;
}


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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--clr-text-primary);
  background-color: var(--clr-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a { color: inherit; text-decoration: none; }
ul { list-style: none; }

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.18;
  letter-spacing: -0.02em;
}


/* ============================================================
   3. Reusable Components
   ============================================================ */

/* --- Section wrapper --- */
.section-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: var(--sp-24) var(--pad-x);
}

/* --- Section header block --- */
.section-header {
  margin-bottom: var(--sp-12);
}

.section-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--clr-accent);
  margin-bottom: var(--sp-2);
}

.section-title {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 700;
  color: var(--clr-text-primary);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 0.6rem 1.4rem;
  border-radius: var(--r-md);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  cursor: pointer;
  white-space: nowrap;
  border: 1.5px solid transparent;
  transition: background var(--t-fast), color var(--t-fast),
              border-color var(--t-fast), transform var(--t-fast),
              box-shadow var(--t-fast);
}

.btn-primary {
  background: var(--clr-accent);
  color: #fff;
  border-color: var(--clr-accent);
}
.btn-primary:hover {
  background: var(--clr-accent-hover);
  border-color: var(--clr-accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(37, 99, 168, 0.30);
}

.btn-ghost {
  background: transparent;
  color: var(--clr-text-secondary);
  border-color: var(--clr-border);
}
.btn-ghost:hover {
  background: var(--clr-surface);
  border-color: var(--clr-text-secondary);
  color: var(--clr-text-primary);
}

.btn-outline {
  background: transparent;
  color: var(--clr-accent);
  border-color: var(--clr-accent);
}
.btn-outline:hover {
  background: var(--clr-accent);
  color: #fff;
}

/* --- Monospace tag/chip --- */
.tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: var(--clr-tag-bg);
  color: var(--clr-tag-text);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  border-radius: var(--r-full);
  border: 1px solid transparent;
  cursor: default;
  transition: background var(--t-fast), color var(--t-fast),
              border-color var(--t-fast);
}
.tag:hover {
  background: var(--clr-accent-light);
  color: var(--clr-accent);
  border-color: var(--clr-accent-subtle);
}


/* ============================================================
   4. Navigation
   ============================================================ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 200;
  height: var(--nav-h);
  background: rgba(245, 247, 251, 0.88);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--clr-border);
  transition: background var(--t-base);
}

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

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--clr-accent);
  letter-spacing: 0.06em;
  flex-shrink: 0;
}

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

.nav-links a {
  font-size: 0.875rem;
  font-weight: 450;
  color: var(--clr-text-secondary);
  transition: color var(--t-fast);
  position: relative;
  padding-bottom: 2px;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -1px; left: 0; right: 0;
  height: 1.5px;
  background: var(--clr-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t-fast);
}

.nav-links a:hover               { color: var(--clr-text-primary); }
.nav-links a:hover::after        { transform: scaleX(1); }
.nav-links a.active              { color: var(--clr-accent); }
.nav-links a.active::after       { transform: scaleX(1); }

/* Hamburger button (hidden on desktop) */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--sp-1);
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--clr-text-primary);
  border-radius: var(--r-full);
  transition: transform var(--t-base), opacity var(--t-base);
}

/* Hamburger → X animation */
.nav-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }


/* ============================================================
   5. Hero Section
   ============================================================ */
.hero {
  min-height: 100svh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-h);
  background-color: var(--clr-bg);
  position: relative;
  overflow: hidden;
}

/* Subtle engineering blueprint grid */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--clr-border) 1px, transparent 1px),
    linear-gradient(90deg, var(--clr-border) 1px, transparent 1px);
  background-size: 52px 52px;
  opacity: 0.50;
  pointer-events: none;
}

/* Radial vignette so grid fades toward center */
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(
    ellipse 80% 80% at 50% 50%,
    transparent 30%,
    var(--clr-bg) 100%
  );
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  max-width: var(--max-w);
  width: 100%;
  margin: 0 auto;
  padding: var(--sp-24) var(--pad-x);
  animation: heroFadeUp 0.7s ease both;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--clr-accent);
  margin-bottom: var(--sp-4);
}

.hero-name {
  font-size: clamp(2.8rem, 8vw, 5.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.0;
  color: var(--clr-text-primary);
  margin-bottom: var(--sp-5);
}

.hero-tagline {
  font-size: clamp(1.05rem, 2.5vw, 1.4rem);
  font-weight: 300;
  color: var(--clr-text-secondary);
  max-width: 560px;
  margin-bottom: var(--sp-4);
  line-height: 1.5;
}

.hero-description {
  font-size: 0.975rem;
  color: var(--clr-text-muted);
  max-width: 520px;
  line-height: 1.75;
  margin-bottom: var(--sp-8);
}

.hero-actions {
  display: flex;
  gap: var(--sp-3);
  flex-wrap: wrap;
}


/* ============================================================
   6. About / Profile Photo Section
   ============================================================ */
.about {
  background: var(--clr-surface);
  border-top: 1px solid var(--clr-border);
  border-bottom: 1px solid var(--clr-border);
}

.about-inner {
  max-width: var(--max-w-text);
  margin: 0 auto;
  padding: var(--sp-24) var(--pad-x);
  text-align: center;
}

.profile-photo-wrap {
  margin: 0 auto var(--sp-8);
  width: 172px;
  height: 172px;
  border-radius: 50%;
  overflow: hidden;
  border: 3px solid var(--clr-border);
  box-shadow: var(--shadow-lg);
  background: var(--clr-surface-alt);
  /* Fallback colour while image loads */
  background-image: linear-gradient(135deg, #dde8f4 0%, #c8d7ec 100%);
}

.profile-photo {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--t-slow);
}

.profile-photo-wrap:hover .profile-photo {
  transform: scale(1.05);
}

.about-name {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--clr-text-primary);
  margin-bottom: var(--sp-2);
}

.about-role {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--clr-accent);
  margin-bottom: var(--sp-6);
  letter-spacing: 0.02em;
}

.about-bio {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--clr-text-secondary);
  max-width: 580px;
  margin: 0 auto;
}


/* ============================================================
   7. Projects Grid
   ============================================================ */
.projects {
  background: var(--clr-bg);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--sp-6);
}

/* Card is now a <div>; links live inside */
.project-card {
  display: flex;
  flex-direction: column;
  background: var(--clr-surface);
  border-radius: var(--r-lg);
  overflow: hidden;
  border: 1px solid var(--clr-border);
  box-shadow: var(--shadow-sm);
  transition: transform var(--t-base), box-shadow var(--t-base),
              border-color var(--t-base);
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: var(--clr-accent-subtle);
}

.project-card-img-link {
  display: block;
  flex-shrink: 0;
}

.project-card-img-wrap {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: linear-gradient(140deg, #d6e4f5 0%, #b8ccec 100%);
}

.project-card-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  transition: transform var(--t-slow);
}

.project-card:hover .project-card-img {
  transform: scale(1.05);
}

.project-card-body {
  padding: var(--sp-4) var(--sp-5) var(--sp-5);
  display: flex;
  flex-direction: column;
  flex: 1;
}

.project-card-title-link {
  text-decoration: none;
  color: inherit;
}

.project-card-title {
  font-size: 0.975rem;
  font-weight: 600;
  color: var(--clr-text-primary);
  letter-spacing: -0.01em;
  line-height: 1.35;
  transition: color var(--t-fast);
}

.project-card-title-link:hover .project-card-title {
  color: var(--clr-accent);
}

.project-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-1);
  margin-top: var(--sp-3);
}

.project-card-tags .tag {
  font-size: 0.7rem;
  padding: 0.18rem 0.55rem;
}

.project-card-actions {
  margin-top: auto;
  padding-top: var(--sp-4);
}

.project-card-pdf {
  font-size: 0.78rem;
  padding: 0.38rem 0.9rem;
}


/* ============================================================
   8. Engineering Toolbox
   ============================================================ */
.toolbox {
  background: var(--clr-surface);
  border-top: 1px solid var(--clr-border);
  border-bottom: 1px solid var(--clr-border);
}

.toolbox-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--sp-10);
}

.toolbox-category-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--clr-text-muted);
  margin-bottom: var(--sp-4);
  padding-bottom: var(--sp-2);
  border-bottom: 1px solid var(--clr-border);
}

.toolbox-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
}


/* ============================================================
   9. CV Section
   ============================================================ */
.cv {
  background: var(--clr-bg);
}

/* Override section-header to accommodate download button */
.cv .section-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--sp-4);
  flex-wrap: wrap;
}

.cv-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-8);
  align-items: start;
}

.cv-column-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--clr-text-muted);
  margin-bottom: var(--sp-4);
  padding-bottom: var(--sp-2);
  border-bottom: 1px solid var(--clr-border);
}

.cv-column-title + .cv-column-title {
  margin-top: var(--sp-8);
}

.cv-card {
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--r-lg);
  padding: var(--sp-5) var(--sp-5);
  margin-bottom: var(--sp-4);
  transition: box-shadow var(--t-base), border-color var(--t-base);
}

.cv-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--clr-accent-subtle);
}

.cv-card-date {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  color: var(--clr-accent);
  display: block;
  margin-bottom: var(--sp-2);
}

.cv-card-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--clr-text-primary);
  margin-bottom: var(--sp-1);
  letter-spacing: -0.01em;
}

.cv-card-org {
  font-size: 0.82rem;
  color: var(--clr-text-secondary);
  margin-bottom: var(--sp-2);
}

.cv-card-desc {
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--clr-text-muted);
}

.cv-section-spacer {
  margin-top: var(--sp-8);
}


/* ============================================================
   10. Footer / Contact Section
   ============================================================ */
.footer {
  background: var(--clr-surface);
  border-top: 1px solid var(--clr-border);
}

.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: var(--sp-20) var(--pad-x) var(--sp-12);
  text-align: center;
}

.footer-title {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--clr-text-primary);
  margin-bottom: var(--sp-3);
}

.footer-sub {
  font-size: 0.975rem;
  color: var(--clr-text-muted);
  max-width: 460px;
  margin: 0 auto var(--sp-10);
  line-height: 1.6;
}

.footer-links {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--sp-4);
  flex-wrap: wrap;
  margin-bottom: var(--sp-12);
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 0.875rem;
  color: var(--clr-text-secondary);
  padding: 0.55rem 1.1rem;
  border-radius: var(--r-full);
  border: 1px solid var(--clr-border);
  background: var(--clr-bg);
  transition: color var(--t-fast), border-color var(--t-fast),
              background var(--t-fast), transform var(--t-fast);
}

.footer-link:hover {
  color: var(--clr-accent);
  border-color: var(--clr-accent-subtle);
  background: var(--clr-accent-light);
  transform: translateY(-1px);
}

.footer-link svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.footer-divider {
  width: 40px;
  height: 1px;
  background: var(--clr-border);
  margin: 0 auto var(--sp-6);
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--clr-text-muted);
}


/* ============================================================
   11. Project Page  (project.html)
   ============================================================ */
.project-page {
  padding-top: var(--nav-h);
  min-height: 100vh;
  background: var(--clr-bg);
}

.project-page-inner {
  max-width: var(--max-w-text);
  margin: 0 auto;
  padding: var(--sp-12) var(--pad-x) var(--sp-24);
}

/* Back link */
.project-back {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--clr-text-muted);
  margin-bottom: var(--sp-8);
  transition: color var(--t-fast);
}

.project-back:hover { color: var(--clr-accent); }
.project-back svg   { width: 14px; height: 14px; }

/* Hero image */
.project-hero-img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--r-xl);
  border: 1px solid var(--clr-border);
  margin-bottom: var(--sp-8);
  background: linear-gradient(140deg, #d6e4f5 0%, #b8ccec 100%);
}

/* Title */
.project-title {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.15;
  color: var(--clr-text-primary);
  margin-bottom: var(--sp-8);
}

/* Tags row below project title */
.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  margin-bottom: var(--sp-8);
}

/* --- Rendered Markdown Content --- */
.project-content {
  color: var(--clr-text-secondary);
  line-height: 1.8;
  font-size: 1rem;
}

.project-content h1,
.project-content h2,
.project-content h3,
.project-content h4 {
  color: var(--clr-text-primary);
  margin-top: var(--sp-8);
  margin-bottom: var(--sp-3);
}

.project-content h2 {
  font-size: 1.35rem;
  padding-bottom: var(--sp-2);
  border-bottom: 1px solid var(--clr-border);
}

.project-content h3 { font-size: 1.1rem; }

.project-content p   { margin-bottom: var(--sp-4); }

.project-content ul,
.project-content ol {
  padding-left: var(--sp-6);
  margin-bottom: var(--sp-4);
}

.project-content li         { margin-bottom: var(--sp-2); list-style: disc; }
.project-content ol > li    { list-style: decimal; }

.project-content strong { font-weight: 600; color: var(--clr-text-primary); }
.project-content em     { font-style: italic; }

.project-content code {
  font-family: var(--font-mono);
  font-size: 0.865em;
  background: var(--clr-surface-alt);
  padding: 0.15em 0.45em;
  border-radius: var(--r-sm);
  color: var(--clr-tag-text);
  border: 1px solid var(--clr-border);
}

.project-content pre {
  background: #1a2030;
  color: #c8d8ee;
  padding: var(--sp-5);
  border-radius: var(--r-lg);
  overflow-x: auto;
  margin-bottom: var(--sp-6);
  font-size: 0.86rem;
  line-height: 1.65;
}

.project-content pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.project-content blockquote {
  border-left: 3px solid var(--clr-accent);
  padding: var(--sp-2) 0 var(--sp-2) var(--sp-5);
  margin: 0 0 var(--sp-4);
  color: var(--clr-text-muted);
  font-style: italic;
}

.project-content img {
  max-width: 100%;
  border-radius: var(--r-lg);
  border: 1px solid var(--clr-border);
  margin: var(--sp-4) 0;
}

.project-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--sp-6);
  font-size: 0.9rem;
}

.project-content th,
.project-content td {
  padding: var(--sp-3) var(--sp-4);
  text-align: left;
  border-bottom: 1px solid var(--clr-border);
}

.project-content th {
  font-weight: 600;
  color: var(--clr-text-primary);
  background: var(--clr-surface-alt);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.project-content a {
  color: var(--clr-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* Download report row */
.project-download {
  margin-top: var(--sp-10);
  padding-top: var(--sp-8);
  border-top: 1px solid var(--clr-border);
}

/* Loading / Error states */
.project-loading {
  padding: var(--sp-20) 0;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--clr-text-muted);
}

.project-error {
  padding: var(--sp-20) 0;
  text-align: center;
  color: var(--clr-text-muted);
}

.project-error h2 {
  font-size: 1.25rem;
  margin-bottom: var(--sp-3);
  color: var(--clr-text-primary);
}


/* ============================================================
   12. Scroll Animations
   ============================================================ */
@keyframes heroFadeUp {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: translateY(0);    }
}

/* Elements that fade in on scroll */
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger delay helpers */
.delay-1 { transition-delay: 0.08s; }
.delay-2 { transition-delay: 0.16s; }
.delay-3 { transition-delay: 0.24s; }
.delay-4 { transition-delay: 0.32s; }


/* ============================================================
   13. Responsive — Tablet (≤ 900px)
   ============================================================ */
@media (max-width: 900px) {
  .cv-grid {
    grid-template-columns: 1fr 1fr;
  }
}


/* ============================================================
   14. Responsive — Mobile (≤ 640px)
   ============================================================ */
@media (max-width: 640px) {

  /* Nav — show hamburger, collapse links */
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-h);
    left: 0; right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--clr-surface);
    border-bottom: 1px solid var(--clr-border);
    box-shadow: var(--shadow-md);
    padding: var(--sp-2) 0;
    z-index: 199;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    display: block;
    padding: var(--sp-3) var(--pad-x);
    font-size: 0.9rem;
  }

  .nav-links a::after { display: none; }

  /* Hero */
  .hero-actions {
    flex-direction: column;
    align-items: flex-start;
  }

  /* CV */
  .cv-grid {
    grid-template-columns: 1fr;
  }

  .cv .section-header {
    flex-direction: column;
    align-items: flex-start;
  }

  /* Toolbox */
  .toolbox-grid {
    grid-template-columns: 1fr;
    gap: var(--sp-8);
  }

  /* Footer */
  .footer-links {
    flex-direction: column;
    align-items: center;
  }
}