/* ============ Reset & Base ============ */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: #f4f6f9;
  color: #1a1a2e;
  line-height: 1.6;
  min-height: 100vh;
}

/* ============ Topbar ============ */
.topbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 20px;
  background: linear-gradient(135deg, #1a3a3a 0%, #0f2a2a 100%);
  box-shadow: 0 2px 12px rgba(0,0,0,0.25);
  gap: 12px;
}
.topbar-left {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.topbar-right {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.btn-top {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  background: rgba(255,255,255,0.1);
  color: #e0e0e0;
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  transition: all 0.2s ease;
}
.btn-top:hover {
  background: rgba(255,255,255,0.2);
  color: #fff;
  border-color: rgba(255,255,255,0.35);
}
.btn-top svg { flex-shrink: 0; }
.lang-select {
  padding: 7px 12px;
  background: rgba(255,255,255,0.12);
  color: #e0e0e0;
  border: 1px solid rgba(255,255,255,0.25);
  border-radius: 6px;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.2s ease;
  min-width: 110px;
}
.lang-select option { color: #1a1a2e; background: #fff; padding: 4px 8px; }
.lang-select:hover {
  background: rgba(255,255,255,0.2);
  color: #fff;
}

/* ============ Container & Header ============ */
.container {
  max-width: 920px;
  margin: 0 auto;
  padding: 28px 20px 48px;
}
.header {
  text-align: center;
  margin-bottom: 24px;
}
.header h1 {
  font-size: 26px;
  font-weight: 700;
  color: #1a3a3a;
  letter-spacing: -0.3px;
}
.header .subtitle {
  font-size: 14px;
  color: #5a6a7a;
  margin-top: 2px;
}

/* ============ Tabs ============ */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  margin-bottom: 20px;
  border-bottom: 2px solid #dde2e8;
}
.tab-btn {
  padding: 8px 12px;
  background: transparent;
  border: none;
  border-bottom: 3px solid transparent;
  font-size: 12.5px;
  font-weight: 600;
  color: #6b7a8d;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}
.tab-btn:hover { color: #1a3a3a; }
.tab-btn.active {
  color: #1a3a3a;
  border-bottom-color: #1a3a3a;
}

/* ============ Panel ============ */
.tab-panel {
  display: none;
  background: #fff;
  border-radius: 12px;
  padding: 28px 28px 24px;
  box-shadow: 0 2px 16px rgba(0,0,0,0.06);
}
.tab-panel.active { display: block; }
.panel-title {
  font-size: 20px;
  font-weight: 700;
  color: #1a3a3a;
  margin-bottom: 6px;
}
.panel-intro {
  font-size: 13.5px;
  color: #5a6a7a;
  margin-bottom: 20px;
}

/* ============ Section ============ */
.section-divider {
  height: 1px;
  background: #e8ecf0;
  margin: 20px 0 16px;
}
.section-label {
  font-size: 15px;
  font-weight: 600;
  color: #1a3a3a;
  margin-bottom: 12px;
}

/* ============ Forms ============ */
.form-row {
  display: flex;
  gap: 16px;
  margin-bottom: 14px;
}
.form-group {
  flex: 1;
  display: flex;
  flex-direction: column;
}
.form-group.cols-2 { flex: 2; }
.form-group.cols-3 { flex: 3; }
.form-group label {
  font-size: 12.5px;
  font-weight: 600;
  color: #3a4a5a;
  margin-bottom: 4px;
}
.form-group input,
.form-group select {
  padding: 9px 12px;
  border: 1.5px solid #d4dae2;
  border-radius: 7px;
  font-size: 14px;
  color: #1a1a2e;
  background: #fafbfc;
  transition: border-color 0.2s ease;
}
.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: #1a3a3a;
  background: #fff;
}
.radio-row {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin-bottom: 16px;
}
.radio-row label {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 13.5px;
  color: #3a4a5a;
  cursor: pointer;
}
.radio-row input[type="radio"] { cursor: pointer; }

/* ============ Button ============ */
.calc-btn-wrap {
  text-align: center;
  margin: 20px 0 16px;
}
.calc-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 32px;
  background: linear-gradient(135deg, #1a5a5a 0%, #1a3a3a 100%);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 14.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.25s ease;
  box-shadow: 0 4px 14px rgba(26,58,58,0.3);
}
.calc-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(26,58,58,0.4);
}
.calc-btn:active { transform: translateY(1px); }

/* ============ Result boxes ============ */
.result {
  display: none;
  padding: 16px 20px;
  border-radius: 8px;
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.7;
}
.result.show { display: block; }
.result.pass {
  background: #eafaf1;
  border: 1.5px solid #27ae60;
  color: #1a5a3a;
}
.result.fail {
  background: #fdf0ed;
  border: 1.5px solid #e74c3c;
  color: #5a1a1a;
}
.result.info {
  background: #eef6fc;
  border: 1.5px solid #2980b9;
  color: #1a3a5a;
}
.result .res-title {
  font-weight: 700;
  font-size: 15.5px;
  margin-bottom: 8px;
}
.result .res-row {
  display: flex;
  justify-content: space-between;
  padding: 3px 0;
  border-bottom: 1px dotted rgba(0,0,0,0.08);
}
.result .res-row:last-child { border-bottom: none; }
.result .res-label { color: #4a5a6a; }
.result .res-value { font-weight: 600; }
.result .res-value.pass-color { color: #27ae60; }
.result .res-value.fail-color { color: #e74c3c; }
.result .cond-list {
  margin: 8px 0 0 18px;
  font-size: 13px;
  line-height: 1.9;
  opacity: 0.85;
}

/* ============ Hard table ============ */
.hard-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 10px;
}
.hard-table th, .hard-table td {
  padding: 8px 10px;
  border: 1.5px solid #dde2e8;
  font-size: 13px;
  text-align: center;
}
.hard-table th {
  background: #f0f4f7;
  font-weight: 600;
  color: #1a3a3a;
}
.hard-table td { background: #fafbfc; }

/* ============ Note Box ============ */
.note-box {
  font-size: 12.5px;
  color: #4a5a6a;
  padding: 10px 14px;
  background: #f7fafb;
  border-left: 3px solid #1a3a3a;
  border-radius: 0 6px 6px 0;
  margin: 12px 0;
  line-height: 1.7;
}

/* ============ Responsive ============ */
@media (max-width: 640px) {
  .form-row { flex-direction: column; gap: 10px; }
  .tabs { flex-direction: column; }
  .tab-btn { text-align: left; border-bottom: none; border-left: 3px solid transparent; }
  .tab-btn.active { border-bottom-color: transparent; border-left-color: #1a3a3a; }
  .container { padding: 16px 12px 32px; }
  .topbar { padding: 8px 14px; }
  .label-full { display: none; }
}