* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, Arial, sans-serif;
  background: #f4f7f4;
  color: #1f2d1f;
}

/* Header */

.app-header {
  background: #2f7d32;
  color: white;
  padding: 12px 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-icon {
  font-size: 28px;
}

.brand-name {
  font-size: 20px;
  font-weight: 700;
}

.brand-sub {
  font-size: 13px;
  opacity: 0.9;
}

/* Navigation */

.main-nav {
  display: flex;
  justify-content: space-around;
  background: rgba(255,255,255,0.15);
  border-radius: 8px;
  padding: 6px;
}

.main-nav a {
  color: white;
  text-decoration: none;
  font-size: 15px;
  padding: 6px 10px;
  border-radius: 6px;
}

.main-nav a:hover {
  background: rgba(255,255,255,0.25);
}

/* Main body */

.app-body {
  padding: 12px;
}

/* Topic cards */

.topic-card {
  background: white;
  border-radius: 14px;
  padding: 14px;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 14px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  text-decoration: none;
  color: #1f2d1f;
}

.topic-card:hover {
  background: #f0f6f0;
}

.topic-icon {
  font-size: 28px;
}

.topic-title {
  font-size: 17px;
  font-weight: 600;
}

/* Buttons */

.button {
  display: block;
  width: 100%;
  padding: 14px;
  border-radius: 12px;
  background: #2f7d32;
  color: white;
  text-align: center;
  text-decoration: none;
  font-size: 18px;
  font-weight: 600;
  margin-top: 12px;
}

.button:hover {
  background: #256428;
}

/* Forms */

.form-box {
  background: white;
  padding: 14px;
  border-radius: 14px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

label {
  display: block;
  margin-bottom: 6px;
  font-weight: 600;
}

input[type=text],
textarea {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #ccc;
  font-size: 16px;
}

textarea {
  min-height: 120px;
}

input:focus,
textarea:focus {
  outline: none;
  border-color: #2f7d32;
}

/* Post list */

.post {
  background: white;
  padding: 12px;
  border-radius: 12px;
  margin-bottom: 10px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

.post-meta {
  font-size: 12px;
  color: #666;
  margin-bottom: 6px;
}

.post-text {
  font-size: 15px;
  line-height: 1.4;
}

/* Footer */

.footer {
  text-align: center;
  font-size: 12px;
  color: #777;
  padding: 12px;
}

/* Desktop improvement */

@media (min-width: 700px) {
  .app-body {
    max-width: 700px;
    margin: auto;
  }

  .main-nav {
    justify-content: center;
    gap: 20px;
  }
}
.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.topic-card {
  flex-direction: column;
  justify-content: center;
  text-align: center;
  padding: 16px;
}

.topic-icon {
  font-size: 36px;
}

.topic-title {
  margin-top: 6px;
  font-size: 14px;
  font-weight: 600;
}