/* ============================================================
   styles.css — Prabu AI Engineer Portfolio
   Theme: white background, gray accents, dark text, clean tech
   ============================================================ */

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

:root {
  --color-bg:         #ffffff;
  --color-surface:    #f8f9fa;
  --color-border:     #e5e7eb;
  --color-text:       #111827;
  --color-text-muted: #6b7280;
  --color-accent:     #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-tag-bg:     #eff6ff;
  --color-tag-text:   #1e40af;
  --font:             'Inter', system-ui, -apple-system, sans-serif;
  --max-width:        1100px;
  --radius:           0.5rem;
  --shadow:           0 1px 4px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
  --transition:       0.2s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--color-accent); text-decoration: none; }
a:hover { color: var(--color-accent-hover); text-decoration: underline; }
ul { list-style: none; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 {
  line-height: 1.25;
  font-weight: 700;
  letter-spacing: -0.01em;
}
h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 3.5vw, 2rem); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1rem; }

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

.text-accent { color: var(--color-accent); font-weight: 600; }
.text-accent-2 { color: #0f766e; font-weight: 600; }
.text-accent-3 { color: #7c3aed; font-weight: 600; }

/* ---------- Layout helpers ---------- */
.container {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: 1.25rem;
}

.section {
  padding-block: 4.5rem;
}

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

.section__header {
  text-align: center;
  margin-bottom: 3rem;
}
.section__header p {
  color: var(--color-text-muted);
  max-width: 540px;
  margin-inline: auto;
  margin-top: 0.5rem;
}

/* ---------- Navigation ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 1px 3px rgba(0,0,0,.04);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav__logo {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: -0.03em;
}
.nav__logo:hover { color: var(--color-accent); text-decoration: none; }

.nav__links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav__links a {
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  font-weight: 500;
  transition: color var(--transition);
}
.nav__links a:hover,
.nav__links a.active { color: var(--color-accent); text-decoration: none; }

.nav__admin {
  display: flex;
  align-items: center;
}
.nav__admin .btn {
  padding: 0.35rem 0.8rem;
  font-size: 0.84rem;
}

/* Hamburger */
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 6px;
  border-radius: var(--radius);
}
.nav__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.nav__toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav__toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav__toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 640px) {
  .nav__toggle { display: flex; }

  .nav__links {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 1.25rem;
    gap: 1rem;
    align-items: flex-start;
  }
  .nav__links.is-open { display: flex; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.9375rem;
  transition: background var(--transition), color var(--transition), box-shadow var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
  line-height: 1.4;
}
.btn--primary {
  background: var(--color-accent);
  color: #fff;
}
.btn--primary:hover {
  background: var(--color-accent-hover);
  text-decoration: none;
  color: #fff;
  box-shadow: 0 4px 12px rgba(37,99,235,.3);
}
.btn--outline {
  background: transparent;
  color: var(--color-accent);
  border-color: var(--color-accent);
}
.btn--outline:hover {
  background: var(--color-accent);
  color: #fff;
  text-decoration: none;
}
.btn--sm { padding: 0.4rem 0.9rem; font-size: 0.875rem; }

/* ---------- Admin panel ---------- */
.admin-panel {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.blog-toolbar {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}
.blog-toolbar__content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}
.blog-toolbar__actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.admin-panel__status {
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.95rem;
}
.modal {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: grid;
  place-items: center;
  padding: 1rem;
}
.modal__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(17, 24, 39, 0.55);
  backdrop-filter: blur(3px);
}
.modal__card {
  position: relative;
  width: min(100%, 440px);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 1rem;
  box-shadow: var(--shadow);
  padding: 1.5rem;
}
.modal__close {
  position: absolute;
  top: 0.85rem;
  right: 0.85rem;
  border: none;
  background: transparent;
  font-size: 1.5rem;
  color: var(--color-text-muted);
  cursor: pointer;
}
.modal__actions {
  display: flex;
  gap: 0.75rem;
  justify-content: flex-end;
  margin-top: 1rem;
}
.form__error {
  margin-top: 0.75rem;
  color: #b91c1c;
  font-size: 0.95rem;
}

/* ---------- Hero ---------- */
.hero {
  padding-block: 6rem 5rem;
  text-align: center;
}
.hero-shell {
  background: linear-gradient(135deg, #f8fbff 0%, #ffffff 70%, #f5f7ff 100%);
  border: 1px solid rgba(37,99,235,.16);
  border-radius: 1.35rem;
  box-shadow: 0 16px 50px rgba(15, 23, 42, 0.06);
  padding: 3rem 2rem;
}
.hero__eyebrow {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 1rem;
  background: var(--color-tag-bg);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
}
.hero h1 { margin-bottom: 1rem; }
.hero__subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: var(--color-text-muted);
  max-width: 600px;
  margin-inline: auto;
  margin-bottom: 2rem;
}
.hero__actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}
.hero__highlights {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1rem;
}
.hero__highlights span {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  background: rgba(37,99,235,.08);
  color: var(--color-accent);
  font-size: 0.875rem;
  font-weight: 600;
}
.hero__admin-link {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}
.hero__admin-note {
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* ---------- Skills strip ---------- */
.skills-strip {
  padding-block: 2rem;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  overflow: hidden;
}
.skills-strip__list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  justify-content: center;
}
.skills-strip__item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  font-weight: 500;
}
.skills-strip__item .dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
  flex-shrink: 0;
}

/* ---------- Cards ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.project-showcase {
  display: grid;
  grid-template-columns: 1.5fr 0.9fr;
  gap: 1.5rem;
  align-items: stretch;
}
.project-showcase__main {
  min-height: 100%;
}
.project-showcase__eyebrow {
  display: inline-flex;
  align-self: flex-start;
  margin-bottom: 0.6rem;
  padding: 0.28rem 0.65rem;
  border-radius: 999px;
  background: rgba(37,99,235,.08);
  color: var(--color-accent);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.project-showcase__side {
  display: grid;
  gap: 1rem;
}
.project-showcase__mini {
  min-height: 0;
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), #7c3aed);
}
.card:hover {
  box-shadow: 0 4px 20px rgba(0,0,0,.12);
  transform: translateY(-2px);
}

.card__title { margin-bottom: 0.5rem; }
.card__desc { color: var(--color-text-muted); font-size: 0.9375rem; flex: 1; }
.card__footer {
  margin-top: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.card__links { display: flex; gap: 0.5rem; }

/* ---------- Tags ---------- */
.tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.75rem; }
.tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
}

/* ---------- Tech stack pill ---------- */
.tech-stack { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.5rem; }
.tech-pill {
  font-size: 0.75rem;
  padding: 0.2rem 0.55rem;
  border-radius: 4px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-weight: 500;
}

/* ---------- Blog list ---------- */
.blog-list { display: flex; flex-direction: column; gap: 1.5rem; }
.blog-card {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1.5rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition), transform var(--transition);
}
.blog-card:hover {
  box-shadow: 0 4px 20px rgba(0,0,0,.12);
  transform: translateY(-2px);
}
.blog-card__meta {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
}
.blog-card__title { font-size: 1.2rem; }
.blog-card__excerpt { color: var(--color-text-muted); font-size: 0.9375rem; }
.blog-card__read-more { font-size: 0.875rem; font-weight: 600; }

/* ---------- Blog post page ---------- */
.post-layout {
  max-width: 720px;
  margin-inline: auto;
  padding-block: 3rem;
}
.post-header { margin-bottom: 2.5rem; }
.post-header h1 { margin-bottom: 0.75rem; }
.post-meta {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}
.post-body h2 { margin: 2rem 0 1rem; }
.post-body h3 { margin: 1.5rem 0 0.75rem; }
.post-body p  { margin-bottom: 1.25rem; }
.post-body ul { list-style: disc; padding-left: 1.5rem; margin-bottom: 1.25rem; }
.post-body li { margin-bottom: 0.4rem; }
.post-body pre {
  background: #f1f5f9;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  overflow-x: auto;
  font-size: 0.875rem;
  margin-bottom: 1.25rem;
}
.post-body code {
  font-family: 'Fira Code', 'Menlo', monospace;
  font-size: 0.875em;
  background: #f1f5f9;
  padding: 0.15em 0.4em;
  border-radius: 3px;
}
.post-body pre code { background: none; padding: 0; }
.post-body blockquote {
  border-left: 4px solid var(--color-accent);
  margin: 1.5rem 0;
  padding: 0.75rem 1.25rem;
  background: var(--color-tag-bg);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--color-text-muted);
}

/* ---------- About page ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 3rem;
  align-items: start;
}
@media (max-width: 700px) {
  .about-grid { grid-template-columns: 1fr; }
  .project-showcase { grid-template-columns: 1fr; }
}
.about-avatar {
  width: 100%;
  max-width: 220px;
  aspect-ratio: 1;
  border-radius: 50%;
  background: var(--color-surface);
  border: 3px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  margin-inline: auto;
}
.skill-list { display: flex; flex-direction: column; gap: 0.75rem; }
.skill-item { display: flex; flex-direction: column; gap: 0.3rem; }
.skill-item__label {
  font-size: 0.875rem;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
}
.skill-bar {
  height: 6px;
  background: var(--color-border);
  border-radius: 999px;
  overflow: hidden;
}
.skill-bar__fill {
  height: 100%;
  background: var(--color-accent);
  border-radius: 999px;
  transition: width 0.8s ease;
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1.25rem;
}
.service-card {
  padding: 1.5rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.service-card__icon { font-size: 2rem; margin-bottom: 0.75rem; }
.service-card h3 { margin-bottom: 0.4rem; }
.service-card p { font-size: 0.9rem; color: var(--color-text-muted); }

/* ---------- Embeddings explainer ---------- */
.embeddings-section { border-left: 4px solid var(--color-accent); padding-left: 1.5rem; }

/* ---------- Contact page ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 3rem;
  align-items: start;
}
@media (max-width: 720px) {
  .contact-grid { grid-template-columns: 1fr; }
}
.contact-info h2 { margin-bottom: 1rem; }
.contact-info p { color: var(--color-text-muted); margin-bottom: 1.5rem; }
.contact-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  font-size: 0.9375rem;
}
.contact-item__icon { font-size: 1.25rem; }

/* Form */
.form { display: flex; flex-direction: column; gap: 1.25rem; }
.form__group { display: flex; flex-direction: column; gap: 0.35rem; }
.form__row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}
@media (max-width: 540px) {
  .form__row { grid-template-columns: 1fr; }
}
.form__label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text);
}
.form__input,
.form__textarea,
.form__select {
  padding: 0.65rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-family: var(--font);
  font-size: 0.9375rem;
  color: var(--color-text);
  background: var(--color-bg);
  transition: border-color var(--transition), box-shadow var(--transition);
  width: 100%;
}
.form__input:focus,
.form__textarea:focus,
.form__select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(37,99,235,.15);
}
.form__input.error,
.form__textarea.error { border-color: #ef4444; }
.form__textarea { resize: vertical; min-height: 140px; }
.form__error {
  font-size: 0.8125rem;
  color: #ef4444;
  display: none;
}
.form__error.visible { display: block; }
.form__status {
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  display: none;
}
.form__status.success { background: #dcfce7; color: #166534; display: block; }
.form__status.error-msg { background: #fee2e2; color: #991b1b; display: block; }

/* ---------- Feature strip (home) ---------- */
.feature-strip {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
}
.feature {
  text-align: center;
  padding: 1.75rem 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
  box-shadow: var(--shadow);
}
.feature:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
}
.feature__icon { font-size: 2.25rem; margin-bottom: 0.75rem; }
.feature h3 { font-size: 1rem; margin-bottom: 0.4rem; }
.feature p { font-size: 0.875rem; color: var(--color-text-muted); margin: 0; }

/* ---------- Pagination (blog) ---------- */
.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 2.5rem;
  flex-wrap: wrap;
}
.page-btn {
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: border-color var(--transition), color var(--transition);
}
.page-btn:hover, .page-btn.active {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ---------- Filter bar (projects / blog) ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 2rem;
}
.filter-btn {
  padding: 0.4rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all var(--transition);
}
.filter-btn:hover, .filter-btn.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding-block: 2.5rem;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.875rem;
}
.site-footer a { color: var(--color-text-muted); }
.site-footer a:hover { color: var(--color-accent); }
.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

/* ---------- Badge / stats strip ---------- */
.stats-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: center;
  padding-block: 3rem;
}
.stat { text-align: center; }
.stat__number {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-accent);
  line-height: 1;
  margin-bottom: 0.25rem;
}
.stat__label { font-size: 0.875rem; color: var(--color-text-muted); }

/* ---------- Back-to-top ---------- */
#back-to-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #fff;
  border: none;
  font-size: 1.1rem;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(37,99,235,.35);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
}
#back-to-top.visible { opacity: 1; pointer-events: auto; }