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

/* === Design Tokens === */
:root {
  /* Colors — Charcoal + Brass */
  --color-primary: #1a1a1a;
  --color-secondary: #6b6b6b;
  --color-accent: #92700a;
  --color-accent-light: #faf6eb;
  --color-dark-bg: #1a1a1a;
  --color-light-bg: #f3f3f0;
  --color-white: #ffffff;
  --color-border: #d4d4d4;
  --color-border-light: #ebebeb;

  /* Problem-Solution-Result colors (charcoal+brass tone) */
  --color-problem-bg: #f5f0f0;
  --color-problem-border: #d4c8c8;
  --color-problem-text: #3d2020;
  --color-problem-label: #8a4040;
  --color-solution-bg: #faf6eb;
  --color-solution-border: #e8dbb3;
  --color-solution-text: #3d3510;
  --color-solution-label: #92700a;
  --color-result-bg: #f2f2ec;
  --color-result-border: #d4d4c0;
  --color-result-text: #2a2a1a;
  --color-result-label: #5a5a20;

  /* Typography */
  --font-family: 'Pretendard Variable', 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  --font-size-xs: 0.75rem;      /* 12px */
  --font-size-sm: 0.8125rem;    /* 13px */
  --font-size-base: 1rem;       /* 16px */
  --font-size-md: 1.0625rem;    /* 17px */
  --font-size-lg: 1.125rem;     /* 18px */
  --font-size-xl: 1.5rem;       /* 24px */
  --font-size-2xl: 1.875rem;    /* 30px */
  --font-size-hero: 2.5rem;     /* 40px */

  /* Layout */
  --max-width: 1080px;
  --section-padding: 80px 24px;
  --card-gap: 16px;
  --card-radius: 12px;
  --nav-height: 64px;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  color: var(--color-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
}

/* === Section backgrounds === */
.section--white { background: var(--color-white); }
.section--hero  { background: #fafaf8; }
.section--light { background: var(--color-light-bg); }
.section--dark  { background: var(--color-dark-bg); color: var(--color-white); }

.section__inner {
  padding: var(--section-padding);
  max-width: var(--max-width);
  margin: 0 auto;
}

/* === Section header === */
.section__label {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 1.5px;
  margin-bottom: 8px;
}

.section--dark .section__label {
  color: #c9a827;
}

.section__title {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-bottom: 8px;
}

.section__subtitle {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
}

.section--dark .section__subtitle {
  color: #999999;
}

/* === Buttons === */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: var(--font-size-base);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: opacity 0.2s;
}

.btn:hover {
  opacity: 0.85;
}

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

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

/* === Cards (3-column grid) === */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--card-gap);
}

/* === Responsive === */
@media (max-width: 768px) {
  :root {
    --section-padding: 56px 20px;
    --font-size-hero: 1.625rem;
    --font-size-2xl: 1.375rem;
  }

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

/* === Nav === */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: 100;
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  padding: 0 24px;
}

.nav__logo {
  font-size: var(--font-size-xl);
  font-weight: 800;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav__link {
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

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

.nav__link--cta {
  background: var(--color-primary);
  color: var(--color-white);
  padding: 8px 20px;
  border-radius: 6px;
}

.nav__link--cta:hover {
  color: var(--color-white);
  opacity: 0.85;
}

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

.nav__hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-primary);
  transition: transform 0.3s;
}

@media (max-width: 768px) {
  .nav__links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-white);
    flex-direction: column;
    padding: 16px 24px;
    gap: 16px;
    border-bottom: 1px solid var(--color-border);
  }

  .nav__links.open {
    display: flex;
  }

  .nav__hamburger {
    display: flex;
  }
}

/* === Hero === */
.hero {
  padding-top: var(--nav-height);
}

.hero__inner {
  padding-top: 96px;
  padding-bottom: 96px;
}

.hero__title {
  font-size: var(--font-size-hero);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -1px;
  margin: 20px 0;
}

.hero__subtitle {
  font-size: var(--font-size-lg);
  color: #475569;
  line-height: 1.8;
  margin-bottom: 36px;
}

.hero__cta {
  display: flex;
  gap: 12px;
}

@media (max-width: 768px) {
  .hero__inner {
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .hero__subtitle br {
    display: none;
  }

  .hero__cta {
    flex-direction: column;
  }

  .hero__cta .btn {
    text-align: center;
  }
}

/* === About === */
.about__header {
  text-align: center;
  margin-bottom: 40px;
}

/* === Trust Statements === */
.trust__card {
  padding: 24px;
  border-left: 3px solid var(--color-accent);
}

.trust__card-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  margin-bottom: 8px;
}

.trust__card-desc {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
  line-height: 1.7;
}

/* === Products === */
.products__cards {
  grid-template-columns: repeat(4, 1fr);
}

.product__card {
  background: var(--color-light-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--card-radius);
  padding: 24px;
  text-align: center;
}

.product__card-title {
  font-size: var(--font-size-base);
  font-weight: 700;
}

@media (max-width: 768px) {
  .products__cards {
    grid-template-columns: 1fr 1fr;
  }
}

/* === About === */
.about__card {
  background: var(--color-white);
  border-radius: var(--card-radius);
  padding: 28px 24px;
  border: 1px solid var(--color-border);
}

.about__card-icon {
  width: 44px;
  height: 44px;
  background: var(--color-accent-light);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  margin-bottom: 16px;
}

.about__card-title {
  font-size: var(--font-size-md);
  font-weight: 700;
  margin-bottom: 8px;
}

.about__card-desc {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
  line-height: 1.7;
}

/* === Portfolio === */
.portfolio__header {
  text-align: center;
  margin-bottom: 40px;
}

.portfolio__cases-header {
  margin-top: 40px;
  margin-bottom: 24px;
}

.portfolio__cases-intro {
  font-size: var(--font-size-xl);
  font-weight: 800;
  color: var(--color-primary);
  text-align: center;
}

.project {
  background: var(--color-light-bg);
  border-radius: 16px;
  padding: 36px;
  margin-bottom: 20px;
  border: 1px solid var(--color-border);
}

.project:last-child {
  margin-bottom: 0;
}

.project__header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 24px;
  flex-wrap: wrap;
  gap: 12px;
}

.project__number {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 1px;
  margin-bottom: 6px;
}

.project__title {
  font-size: var(--font-size-xl);
  font-weight: 800;
}

.project__tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.tag {
  background: var(--color-accent-light);
  color: var(--color-accent);
  font-size: var(--font-size-xs);
  padding: 4px 10px;
  border-radius: 4px;
  font-weight: 500;
}

/* Problem → Solution → Result (vertical) */
.project__psr--vertical {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.psr {
  border-radius: 10px;
  padding: 20px;
}

.psr--large {
  padding: 28px 32px;
}

.psr--problem {
  background: var(--color-problem-bg);
  border: 1px solid var(--color-problem-border);
}

.psr--solution {
  background: var(--color-solution-bg);
  border: 1px solid var(--color-solution-border);
}

.psr--result {
  background: var(--color-result-bg);
  border: 1px solid var(--color-result-border);
}

.psr__label {
  font-size: var(--font-size-xs);
  font-weight: 700;
  margin-bottom: 8px;
}

.psr--problem .psr__label { color: var(--color-problem-label); }
.psr--solution .psr__label { color: var(--color-solution-label); }
.psr--result .psr__label { color: var(--color-result-label); }

.psr__title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 6px;
}

.psr--problem .psr__title { color: var(--color-problem-text); }
.psr--solution .psr__title { color: var(--color-solution-text); }
.psr--result .psr__title { color: var(--color-result-text); }

.psr__desc {
  font-size: var(--font-size-base);
  line-height: 1.7;
}

.psr--problem .psr__desc { color: var(--color-problem-text); opacity: 0.7; }
.psr--solution .psr__desc { color: var(--color-solution-text); opacity: 0.7; }
.psr--result .psr__desc { color: var(--color-result-text); opacity: 0.7; }

.psr__arrow {
  display: flex;
  align-items: center;
  font-size: 20px;
  color: #cbd5e1;
}

.psr__arrow--down {
  justify-content: center;
  padding: 8px 0;
  font-size: 18px;
}

/* Architecture SVG diagram */
.project__arch {
  margin-top: 20px;
  padding: 28px 24px;
  background: var(--color-dark-bg);
  border-radius: 10px;
  color: var(--color-white);
}

/* Strategy tags */
.project__strategies {
  margin-top: 24px;
  margin-bottom: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.project__strategies-group {}

.project__strategies-label {
  font-size: var(--font-size-xs);
  font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 1px;
  margin-bottom: 12px;
  text-transform: uppercase;
}

.project__strategies-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.strategy-tag {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  padding: 8px 16px;
  border-radius: 8px;
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-primary);
}

/* Module cards (3-column) */
.modules-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--card-gap);
  margin-top: 24px;
}

.module-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--card-radius);
  padding: 24px;
}

.module-card__title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--color-primary);
}

.module-card__desc {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}

.module-card__features {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

@media (max-width: 768px) {
  .modules-grid {
    grid-template-columns: 1fr;
  }
}

.strategy-tag--feature {
  background: transparent;
  border-style: dashed;
  color: var(--color-secondary);
}

/* Common Features Cards */
.common-features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 12px;
}

.common-feature__card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.common-feature__icon {
  font-size: 20px;
  flex-shrink: 0;
}

.common-feature__title {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-primary);
}

@media (max-width: 768px) {
  .common-features__grid {
    grid-template-columns: 1fr;
  }
}

/* Track Record */
.track-record__list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.track-record__item {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-primary);
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
  position: relative;
  padding-left: 24px;
}

.track-record__item::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: 700;
}

.track-record__item:last-child {
  border-bottom: none;
}

/* Screenshots */
.screenshot-context {
  font-size: var(--font-size-sm);
  color: #999;
  text-align: center;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.project__screenshots {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.project__screenshots .project__screenshot {
  width: 100%;
}

@media (max-width: 768px) {
  .project__screenshots {
    grid-template-columns: 1fr;
  }
}

.project__screenshot {
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid #3a3a3a;
}

.screenshot-placeholder {
  background: #2a2a2a;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  color: #999;
  font-size: var(--font-size-base);
  font-weight: 600;
  gap: 8px;
}

.screenshot-placeholder__sub {
  font-size: var(--font-size-xs);
  font-weight: 400;
  color: #666;
}

.project__screenshot img {
  width: 100%;
  height: auto;
  display: block;
}

.screenshot-caption {
  padding: 12px 16px;
  font-size: var(--font-size-sm);
  color: #999;
  background: #2a2a2a;
}

.project__arch-intro {
  font-size: var(--font-size-md);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: 16px;
  line-height: 1.6;
}

.project__arch-label {
  font-size: var(--font-size-xs);
  color: #c9a827;
  font-weight: 600;
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.arch-svg {
  width: 100%;
  height: auto;
  font-family: var(--font-family);
}

/* Legacy text diagram (unused, kept for reference) */
.arch-node {
  background: var(--color-dark-bg);
  color: var(--color-white);
  padding: 8px 14px;
  border-radius: 6px;
  font-size: var(--font-size-sm);
  font-weight: 600;
  text-align: center;
}

.arch-node span {
  display: block;
  font-size: 10px;
  color: #999999;
  font-weight: 400;
}

.arch-node--sm {
  padding: 6px 14px;
  font-size: var(--font-size-xs);
}

.arch-connector {
  color: #cbd5e1;
  font-size: var(--font-size-lg);
}

.arch-clients {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

/* Portfolio responsive */
@media (max-width: 768px) {
  .project {
    padding: 24px 20px;
  }

  .psr--large {
    padding: 20px;
  }

  .project__arch-diagram {
    flex-direction: column;
    gap: 8px;
  }

  .arch-connector {
    transform: rotate(90deg);
  }
}

/* === Capability === */
.capability__header {
  text-align: center;
  margin-bottom: 44px;
}

.capability__card {
  background: #2a2a2a;
  border-radius: var(--card-radius);
  padding: 28px 24px;
  border: 1px solid #3a3a3a;
}

.capability__card-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  margin-bottom: 18px;
}

.capability__card-icon--tech { background: rgba(201, 168, 39, 0.15); }
.capability__card-icon--logic { background: rgba(201, 168, 39, 0.12); }
.capability__card-icon--exp { background: rgba(201, 168, 39, 0.10); }

.capability__card-label {
  font-size: var(--font-size-xs);
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 6px;
}

.capability__card-label--tech { color: #c9a827; }
.capability__card-label--logic { color: #d4b63a; }
.capability__card-label--exp { color: #b89c1e; }

.capability__card-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.4;
}

.capability__card-desc {
  font-size: var(--font-size-base);
  color: #999999;
  line-height: 1.8;
}

.capability__footer {
  margin-top: 32px;
  text-align: center;
  padding: 20px;
  border-top: 1px solid #3a3a3a;
  font-size: var(--font-size-md);
  color: #999999;
  line-height: 1.8;
}

.capability__footer strong {
  color: var(--color-white);
}

/* === Contact === */
.contact__inner {
  max-width: 640px;
  margin: 0 auto;
}

.contact__header {
  text-align: left;
  margin-bottom: 36px;
}

.contact__reasons {
  list-style: none;
  margin: 16px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.contact__reasons li {
  font-size: var(--font-size-base);
  color: var(--color-secondary);
  padding-left: 16px;
  position: relative;
}

.contact__reasons li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: 700;
}

.contact__guide {
  font-size: var(--font-size-base);
  color: var(--color-primary);
  line-height: 1.7;
  margin-top: 16px;
  padding: 16px;
  background: var(--color-white);
  border-radius: 8px;
  border: 1px solid var(--color-border);
}

.contact__form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.form__field {
  display: flex;
  flex-direction: column;
}

.form__label {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: #475569;
  margin-bottom: 6px;
}

.form__input {
  font-family: var(--font-family);
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 12px 16px;
  font-size: var(--font-size-base);
  color: var(--color-primary);
  transition: border-color 0.2s;
}

.form__input:focus {
  outline: none;
  border-color: var(--color-accent);
}

.form__input::placeholder {
  color: #999999;
}

.form__textarea {
  min-height: 100px;
  resize: vertical;
}

.contact__submit {
  margin-top: 4px;
  width: 100%;
  text-align: center;
}

/* === Footer === */
.footer {
  background: var(--color-dark-bg);
  color: var(--color-white);
}

.footer__inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 32px 24px;
}

.footer__logo {
  font-size: var(--font-size-base);
  font-weight: 700;
  margin-bottom: 4px;
}

.footer__copyright {
  font-size: var(--font-size-sm);
  color: var(--color-secondary);
}

.footer__links {
  display: flex;
  gap: 20px;
}

.footer__link {
  font-size: var(--font-size-sm);
  color: #999999;
  text-decoration: none;
  transition: color 0.2s;
}

.footer__link:hover {
  color: var(--color-white);
}

@media (max-width: 768px) {
  .footer__inner {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
}

/* === Scroll animation === */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}