/* ===========================
   ISData Consulting — styles.css
   Design System: Dark-first, minimal, typographic
   =========================== */

/* --- CSS Variables --- */
:root {
  --black: #0a0a0a;
  --black-alt: #0f0f0f;
  --white: #f5f3ef;
  --accent: #c8f04d;
  --gray: #888888;
  --border: #2a2a2a;
  --font-serif: 'Instrument Serif', Georgia, serif;
  --font-mono: 'DM Mono', 'Courier New', monospace;
  --font-body: 'Geist', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

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

body {
  font-family: var(--font-body);
  font-weight: 300;
  color: var(--white);
  background: var(--black);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

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

/* --- Typography --- */
h1,
h2,
h3 {
  font-family: var(--font-serif);
  font-weight: 400;
  line-height: 1.15;
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  letter-spacing: -0.02em;
}

h1 em {
  font-style: italic;
}

h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  letter-spacing: -0.02em;
  margin-bottom: 3rem;
}

h3 {
  font-size: 1.3rem;
  margin-bottom: 0.75rem;
}

/* --- Layout --- */
.section-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section {
  padding: 8rem 0;
}

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

.section-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 1rem;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 10, 10, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: 0.05em;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
}

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--gray);
  transition: color 0.3s ease;
}

.nav-links a:hover {
  color: var(--white);
}

.nav-cta {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--black);
  background: var(--accent);
  padding: 0.5rem 1.25rem;
  border-radius: 4px;
  transition:
    opacity 0.3s ease,
    transform 0.3s ease;
}

.nav-cta:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--white);
  transition:
    transform 0.3s ease,
    opacity 0.3s ease;
}

.nav-hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-hamburger.active span:nth-child(2) {
  opacity: 0;
}

.nav-hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.nav-mobile {
  display: none;
  flex-direction: column;
  padding: 1rem 2rem 2rem;
  border-top: 1px solid var(--border);
}

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

.nav-mobile a {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--gray);
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.3s ease;
}

.nav-mobile a:hover {
  color: var(--white);
}

.nav-cta-mobile {
  margin-top: 0.5rem;
  color: var(--accent) !important;
  border-bottom: none !important;
}

/* --- Hero --- */
.hero {
  padding: 10rem 0 8rem;
  min-height: 100vh;
  display: flex;
  align-items: center;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 4rem;
  align-items: center;
}

.hero-content h1 {
  margin-bottom: 1.5rem;
}

.hero-sub {
  font-size: 1.1rem;
  color: var(--gray);
  max-width: 540px;
  margin-bottom: 1rem;
  line-height: 1.8;
}

.hero-proof {
  max-width: 560px;
  margin-bottom: 2.2rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--white);
  border-left: 2px solid var(--accent);
  padding-left: 0.9rem;
}

.hero-side {
  display: grid;
  gap: 0;
  justify-items: stretch;
}

.hero-profile {
  width: 100%;
  max-width: 360px;
  margin-left: auto;
  border: 1px solid var(--border);
  background: var(--black-alt);
  overflow: hidden;
}

.hero-profile img {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  object-position: center top;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 0.75rem 1.75rem;
  border-radius: 4px;
  transition:
    transform 0.3s ease,
    opacity 0.3s ease;
  display: inline-block;
}

.btn:hover {
  transform: translateY(-1px);
}

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

.btn-primary:hover {
  opacity: 0.9;
}

.btn-secondary {
  background: transparent;
  color: var(--white);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--gray);
}

/* --- Constat --- */
.constat-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}

.problem-list li {
  font-size: 1.05rem;
  color: var(--gray);
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.3s ease;
  cursor: default;
}

.problem-list li::before {
  content: '— ';
  color: var(--accent);
}

.problem-list li:hover {
  color: var(--white);
}

.problem-list li:first-child {
  border-top: 1px solid var(--border);
}

/* --- Services --- */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  margin-top: 1rem;
}

.service-card {
  background: var(--black);
  padding: 2.5rem;
  transition: background 0.3s ease;
}

.service-card:hover {
  background: #111;
}

.service-number {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  display: block;
  margin-bottom: 1.5rem;
}

.service-card h3 {
  font-size: 1.4rem;
  margin-bottom: 1rem;
}

.service-card p {
  color: var(--gray);
  font-size: 0.95rem;
  line-height: 1.7;
  margin-bottom: 1.2rem;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-content: flex-start;
}

.tags span {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  line-height: 1;
  letter-spacing: 0.01em;
  white-space: nowrap;
  color: var(--accent);
  border: 1px solid #33401a;
  background: rgba(200, 240, 77, 0.06);
  padding: 0.3rem 0.55rem;
  border-radius: 3px;
}

/* --- Experience --- */
.experience-list {
  margin-top: 1rem;
}

.experience-item {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 3rem;
  padding: 2.5rem 0;
  border-bottom: 1px solid var(--border);
}

.experience-item:first-child {
  border-top: 1px solid var(--border);
}

.experience-meta {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.experience-company {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  color: var(--white);
}

.experience-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
}

.experience-location {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--gray);
}

.experience-role {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  display: block;
  margin-bottom: 0.75rem;
}

.experience-content p {
  color: var(--gray);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* --- Approche --- */
.approche-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}

.approche-card {
  background: var(--black);
  padding: 2.5rem;
  transition: background 0.3s ease;
}

.approche-card:hover {
  background: #111;
}

.approche-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}

.approche-card p {
  color: var(--gray);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* --- Contact --- */
.contact-content {
  max-width: 600px;
}

.contact-sub {
  color: var(--gray);
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 2.5rem;
}

.contact-links {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: 2rem;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.3s ease;
}

.contact-link:first-child {
  border-top: 1px solid var(--border);
}

.contact-link:hover .contact-link-value {
  color: var(--accent);
}

.contact-link-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--gray);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  min-width: 80px;
}

.contact-link-value {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--white);
  transition: color 0.3s ease;
}

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer span {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--gray);
  letter-spacing: 0.05em;
}

/* --- Scroll Reveal --- */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition:
    opacity 0.6s ease,
    transform 0.6s ease;
}

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

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--black);
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}

/* ===========================
   RESPONSIVE — max-width: 900px
   =========================== */
@media (max-width: 900px) {
  .section {
    padding: 5rem 0;
  }

  .nav-links,
  .nav-cta {
    display: none;
  }

  .nav-hamburger {
    display: flex;
  }

  .hero {
    padding: 8rem 0 5rem;
    min-height: auto;
  }

  .hero-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .hero-side {
    justify-items: stretch;
  }

  .hero-profile {
    max-width: 340px;
    margin-left: 0;
  }

  .constat-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .services-grid {
    grid-template-columns: 1fr;
  }

  .experience-item {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .approche-grid {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    flex-direction: column;
    gap: 0.5rem;
    text-align: center;
  }
}

/* Fine adjustments for very small screens */
@media (max-width: 480px) {
  .section-inner {
    padding: 0 1.25rem;
  }

  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.6rem;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn {
    text-align: center;
  }

  .contact-link {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.25rem;
  }

  .tags {
    gap: 0.35rem;
  }

  .tags span {
    font-size: 0.64rem;
    padding: 0.26rem 0.45rem;
  }
}