:root {
  --bg: #f7f8fc;
  --surface: #ffffff;
  --text: #1f2a37;
  --muted: #5b6472;
  --primary: #4655d4;
  --primary-hover: #3844b0;
  --border: #e6e9f2;
  --shadow: 0 6px 20px rgba(43, 51, 69, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  width: min(1100px, 92%);
  margin: 0 auto;
}

.hero {
  background: linear-gradient(135deg, #eef1ff 0%, #f9fbff 100%);
  border-bottom: 1px solid var(--border);
  padding-bottom: 3rem;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.logo {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.nav ul {
  list-style: none;
  display: flex;
  gap: 1rem;
  padding: 0;
  margin: 0;
}

.nav li + li {
  border-left: 1px solid #cfd5e6;
  padding-left: 1rem;
}

.nav a {
  text-decoration: none;
  color: var(--muted);
}

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

.hero-content {
  padding: 3rem 0 1rem;
}

.eyebrow {
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 0.25rem;
}

h1,
h2,
h3 {
  line-height: 1.3;
}

h1 {
  margin-top: 0;
  margin-bottom: 0.75rem;
}

.section {
  padding: 3rem 0;
}

.grid {
  display: grid;
  gap: 1rem;
}

.grid.two {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid.three {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1rem;
  box-shadow: var(--shadow);
}

.card a {
  color: var(--primary);
  text-decoration: none;
}

.project p {
  margin: 0.35rem 0;
}

.project-example {
  margin-top: 0.7rem;
}

.project-example summary {
  display: inline-block;
  cursor: pointer;
  list-style: none;
}

.project-example summary::-webkit-details-marker {
  display: none;
}

.project-image {
  width: 100%;
  margin-top: 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--border);
}

.project-image-placeholder {
  margin-top: 0.75rem;
  padding: 1.5rem 0.8rem;
  text-align: center;
  color: var(--muted);
  border: 1px dashed var(--border);
  border-radius: 10px;
  background: #fafbff;
}

.hero-actions {
  display: flex;
  gap: 0.8rem;
  margin-top: 1.25rem;
  flex-wrap: wrap;
}

.btn {
  border: 1px solid var(--border);
  padding: 0.6rem 1rem;
  border-radius: 10px;
  text-decoration: none;
  color: var(--text);
  background: #fff;
  font-weight: 500;
}

.btn.primary {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

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

.contact-list p {
  margin: 0.5rem 0;
}

.footer {
  border-top: 1px solid var(--border);
  padding: 1.2rem 0;
  background: #fff;
}

.modal.hidden {
  display: none;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.45);
}

.modal-content {
  position: relative;
  width: min(560px, 90%);
  margin: 18vh auto 0;
  background: #fff;
  border-radius: 14px;
  padding: 1.2rem 1.2rem 1rem;
  box-shadow: var(--shadow);
  z-index: 1;
}

.modal-close {
  border: none;
  background: transparent;
  font-size: 1.4rem;
  line-height: 1;
  position: absolute;
  top: 0.6rem;
  right: 0.8rem;
  cursor: pointer;
}

@media (max-width: 900px) {
  .grid.two,
  .grid.three {
    grid-template-columns: 1fr;
  }

  .nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .nav ul {
    flex-wrap: wrap;
  }
}