/* =============================================
   Progressive Tech Institute — styles.css
   Design principles: calm, clear, human
   ============================================= */

:root {
  --ink: #0F172A;
  --text: #1E293B;
  --muted: #64748B;
  --border: #E2E8F0;
  --surface: #F8FAFC;
  --white: #FFFFFF;
  --green: #059669;
  --green-light: #D1FAE5;
  --green-mid: #6EE7B7;
  --indigo: #4F46E5;
  --indigo-light: #EEF2FF;
  --amber: #D97706;
  --amber-light: #FEF3C7;
  --rose: #E11D48;
  --rose-light: #FFE4E6;
  --teal: #0891B2;
  --teal-light: #CFFAFE;
  --violet: #7C3AED;
  --violet-light: #EDE9FE;
  --sky: #0284C7;
  --sky-light: #E0F2FE;

  --radius: 12px;
  --radius-sm: 6px;
  --shadow: 0 1px 3px rgba(0,0,0,0.07), 0 4px 12px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.10);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'Fraunces', Georgia, serif;
  --transition: 200ms ease;
}

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

html { scroll-behavior: smooth; }

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

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ---- Layout ---- */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 96px 0; }

/* ---- Nav ---- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 32px;
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--ink);
  flex-shrink: 0;
}

.nav__logo-mark {
  width: 32px;
  height: 32px;
  background: var(--ink);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav__links a {
  font-size: 14px;
  color: var(--muted);
  font-weight: 500;
  transition: color var(--transition);
}

.nav__links a:hover { color: var(--ink); }

.nav__cta {
  background: var(--ink);
  color: white !important;
  padding: 8px 18px;
  border-radius: var(--radius-sm);
  font-size: 14px !important;
  font-weight: 600 !important;
  transition: opacity var(--transition) !important;
}

.nav__cta:hover { opacity: 0.85; color: white !important; }

/* ---- Hero ---- */
.hero {
  padding: 120px 0 96px;
  background: var(--ink);
  color: white;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 70% 40%, rgba(5,150,105,0.18) 0%, transparent 70%),
    radial-gradient(ellipse 40% 60% at 20% 80%, rgba(79,70,229,0.15) 0%, transparent 70%);
  pointer-events: none;
}

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--green-mid);
  margin-bottom: 24px;
}

.hero__eyebrow-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--green-mid);
}

.hero__headline {
  font-family: var(--font-display);
  font-size: clamp(40px, 6vw, 72px);
  font-weight: 900;
  line-height: 1.08;
  letter-spacing: -0.03em;
  max-width: 720px;
  margin-bottom: 28px;
}

.hero__headline em {
  font-style: normal;
  color: var(--green-mid);
}

.hero__sub {
  font-size: clamp(17px, 2.2vw, 20px);
  color: rgba(255,255,255,0.65);
  max-width: 560px;
  line-height: 1.65;
  margin-bottom: 48px;
}

.hero__actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 26px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
}

.btn--primary {
  background: var(--green);
  color: white;
}
.btn--primary:hover { background: #047857; }

.btn--ghost {
  background: transparent;
  color: rgba(255,255,255,0.75);
  border: 1px solid rgba(255,255,255,0.2);
}
.btn--ghost:hover { background: rgba(255,255,255,0.08); color: white; }

.hero__stats {
  display: flex;
  gap: 48px;
  margin-top: 72px;
  padding-top: 48px;
  border-top: 1px solid rgba(255,255,255,0.1);
  flex-wrap: wrap;
}

.hero__stat-value {
  font-size: 36px;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: white;
  line-height: 1;
  margin-bottom: 4px;
}

.hero__stat-label {
  font-size: 13px;
  color: rgba(255,255,255,0.45);
  font-weight: 500;
}

/* ---- Problem ---- */
.problem {
  background: var(--surface);
}

.section-label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 16px;
}

.section-headline {
  font-family: var(--font-display);
  font-size: clamp(30px, 4vw, 46px);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.025em;
  color: var(--ink);
  max-width: 640px;
  margin-bottom: 20px;
}

.section-sub {
  font-size: 18px;
  color: var(--muted);
  max-width: 580px;
  line-height: 1.7;
  margin-bottom: 56px;
}

.problem__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.problem-card {
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
}

.problem-card__icon {
  font-size: 28px;
  margin-bottom: 16px;
}

.problem-card__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.problem-card__body {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
}

/* ---- Focus Areas ---- */
.focus-areas { background: white; }

.focus-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-top: 56px;
}

.focus-item {
  background: white;
  padding: 36px 32px;
  transition: background var(--transition);
  position: relative;
}

.focus-item:hover { background: var(--surface); }

.focus-item__tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 100px;
  margin-bottom: 20px;
}

.focus-item__number {
  font-size: 11px;
  font-weight: 800;
  color: var(--muted);
  opacity: 0.5;
  position: absolute;
  top: 24px;
  right: 24px;
}

.focus-item__title {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.02em;
  margin-bottom: 12px;
  line-height: 1.3;
}

.focus-item__body {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.focus-item__learn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 13px;
  font-weight: 600;
  margin-top: 16px;
  opacity: 0.7;
  transition: opacity var(--transition);
}

.focus-item:hover .focus-item__learn { opacity: 1; }

/* tag color variants */
.tag--green { background: var(--green-light); color: #065F46; }
.tag--indigo { background: var(--indigo-light); color: #3730A3; }
.tag--amber { background: var(--amber-light); color: #92400E; }
.tag--rose { background: var(--rose-light); color: #9F1239; }
.tag--teal { background: var(--teal-light); color: #155E75; }
.tag--violet { background: var(--violet-light); color: #5B21B6; }
.tag--sky { background: var(--sky-light); color: #075985; }
.tag--gray { background: #F1F5F9; color: #475569; }

/* ---- Active focus card ---- */
.focus-active {
  display: block;
  background: var(--ink);
  color: white;
  border-radius: var(--radius);
  padding: 40px 44px;
  margin-top: 48px;
  text-decoration: none;
  position: relative;
  overflow: hidden;
  transition: opacity var(--transition);
}

.focus-active::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 60% 80% at 90% 50%, rgba(5,150,105,0.18) 0%, transparent 65%);
  pointer-events: none;
}

.focus-active:hover { opacity: 0.92; }

.focus-active__badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--green-mid);
  margin-bottom: 16px;
}

.focus-active__badge::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--green-mid);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.focus-active__tag {
  display: inline-flex;
  margin-bottom: 16px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 100px;
}

.focus-active__title {
  font-family: var(--font-display);
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 800;
  color: white;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin-bottom: 16px;
  max-width: 640px;
}

.focus-active__body {
  font-size: 16px;
  color: rgba(255,255,255,0.6);
  line-height: 1.7;
  max-width: 680px;
  margin-bottom: 20px;
}

.focus-active__meta {
  display: flex;
  gap: 10px;
  font-size: 13px;
  color: rgba(255,255,255,0.35);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.focus-active__cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 700;
  color: var(--green-mid);
}

/* ---- Future grid ---- */
.future-header {
  margin-top: 72px;
  margin-bottom: 28px;
  padding-top: 48px;
  border-top: 1px solid var(--border);
}

.future-grid {
  margin-top: 0 !important;
}

.focus-item--future {
  opacity: 0.65;
  transition: opacity var(--transition), background var(--transition);
}

.focus-item--future:hover {
  opacity: 1;
  background: var(--surface);
}

.focus-item--future .focus-item__title {
  font-size: 16px;
}

/* ---- Approach ---- */
.approach {
  background: var(--ink);
  color: white;
}

.approach .section-headline { color: white; }
.approach .section-sub { color: rgba(255,255,255,0.55); }

.approach-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px;
  margin-top: 56px;
}

.approach-item__number {
  font-size: 40px;
  font-weight: 900;
  color: var(--green-mid);
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 16px;
  opacity: 0.7;
}

.approach-item__title {
  font-size: 17px;
  font-weight: 700;
  color: white;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.approach-item__body {
  font-size: 14px;
  color: rgba(255,255,255,0.5);
  line-height: 1.7;
}

/* ---- Principles ---- */
.principles { background: var(--surface); }

.principles-list {
  margin-top: 48px;
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: white;
  box-shadow: var(--shadow);
}

.principle {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 0;
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}

.principle:last-child { border-bottom: none; }
.principle:hover { background: var(--surface); }

.principle__num {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  font-weight: 900;
  color: var(--border);
  border-right: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
}

.principle__body {
  padding: 28px 32px;
}

.principle__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 6px;
  letter-spacing: -0.01em;
}

.principle__text {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
}

/* ---- Join ---- */
.join {
  background: white;
  text-align: center;
}

.join .section-headline,
.join .section-sub {
  margin-left: auto;
  margin-right: auto;
}

.join .section-sub { margin-bottom: 40px; }

.join__cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 48px;
  text-align: left;
}

.join-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: box-shadow var(--transition), transform var(--transition);
}

.join-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.join-card__icon {
  font-size: 26px;
  margin-bottom: 14px;
}

.join-card__title {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.join-card__body {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.65;
  margin-bottom: 16px;
}

.join-card__link {
  font-size: 13px;
  font-weight: 700;
  color: var(--green);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* ---- Newsletter ---- */
.newsletter {
  background: var(--ink);
  color: white;
  text-align: center;
  padding: 80px 0;
}

.newsletter__headline {
  font-family: var(--font-display);
  font-size: clamp(26px, 4vw, 40px);
  font-weight: 800;
  letter-spacing: -0.03em;
  color: white;
  margin-bottom: 12px;
}

.newsletter__sub {
  font-size: 16px;
  color: rgba(255,255,255,0.5);
  margin-bottom: 32px;
}

.newsletter__form {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  max-width: 480px;
  margin: 0 auto;
}

.newsletter__input {
  flex: 1;
  min-width: 200px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255,255,255,0.15);
  background: rgba(255,255,255,0.08);
  color: white;
  font-size: 15px;
  font-family: var(--font);
  outline: none;
  transition: border-color var(--transition);
}

.newsletter__input::placeholder { color: rgba(255,255,255,0.35); }
.newsletter__input:focus { border-color: var(--green-mid); }

.newsletter__btn {
  padding: 12px 24px;
  background: var(--green);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  transition: background var(--transition);
  white-space: nowrap;
}

.newsletter__btn:hover { background: #047857; }

.newsletter__note {
  font-size: 12px;
  color: rgba(255,255,255,0.3);
  margin-top: 12px;
}

/* ---- Footer ---- */
.footer {
  background: var(--ink);
  border-top: 1px solid rgba(255,255,255,0.07);
  padding: 48px 0;
  color: rgba(255,255,255,0.4);
}

.footer__inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 40px;
}

.footer__brand { grid-column: 1; }

.footer__brand-name {
  font-weight: 800;
  font-size: 15px;
  color: white;
  letter-spacing: -0.01em;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer__brand-desc {
  font-size: 13px;
  line-height: 1.65;
  max-width: 260px;
}

.footer__col-title {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.6);
  margin-bottom: 16px;
}

.footer__links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer__links a {
  font-size: 13px;
  color: rgba(255,255,255,0.4);
  transition: color var(--transition);
}

.footer__links a:hover { color: rgba(255,255,255,0.9); }

.footer__bottom {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.07);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 12px;
}

.footer__bottom a {
  color: rgba(255,255,255,0.35);
  transition: color var(--transition);
}

.footer__bottom a:hover { color: rgba(255,255,255,0.7); }

/* ---- Utilities ---- */
.text-green { color: var(--green); }

/* ---- Responsive ---- */
@media (max-width: 768px) {
  section { padding: 72px 0; }
  .hero { padding: 80px 0 72px; }

  .nav__links { display: none; }

  .hero__stats { gap: 32px; }

  .footer__inner {
    grid-template-columns: 1fr 1fr;
  }
  .footer__brand { grid-column: 1 / -1; }

  .principle {
    grid-template-columns: 56px 1fr;
  }
}

@media (max-width: 520px) {
  .footer__inner { grid-template-columns: 1fr; }
  .hero__stats { flex-direction: column; gap: 24px; }
}