/* ===== Global ===== */
* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --panel-2: #273449;
  --border: #334155;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
  --accent: #38bdf8;
  --accent-2: #818cf8;
  --v1: #f59e0b;   /* ΔV1 - amber */
  --v2: #10b981;   /* ΔV2 - emerald */
  --v3: #ef4444;   /* ΔV3 - red */
  --voc: #38bdf8;  /* VOC */
  --voc-sq: #a78bfa;
}

body {
  font-family: 'Segoe UI', 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

.app {
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px 20px 60px;
}

/* ===== Header ===== */
.header {
  text-align: center;
  padding: 18px 0 28px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 28px;
}
.header h1 {
  font-size: 26px;
  font-weight: 700;
  letter-spacing: 0.3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.header p {
  color: var(--text-dim);
  font-size: 14px;
  margin-top: 6px;
}

/* ===== Layout ===== */
.layout {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 24px;
}
@media (max-width: 960px) {
  .layout { grid-template-columns: 1fr; }
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}

.panel-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
  text-transform: uppercase;
  letter-spacing: 0.6px;
}
.panel-title::before {
  content: '';
  width: 4px;
  height: 14px;
  background: var(--accent);
  border-radius: 2px;
}

/* ===== Inputs ===== */
.field { margin-bottom: 16px; }
.field label {
  display: block;
  font-size: 13px;
  color: var(--text-dim);
  margin-bottom: 6px;
}
.field label .unit { color: #64748b; font-size: 12px; margin-left: 4px; }

.input {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  transition: border-color 0.15s;
}
.input:focus {
  outline: none;
  border-color: var(--accent);
}

.row-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

/* ===== JSC radio toggle ===== */
.jsc-toggle {
  display: flex;
  gap: 16px;
  margin-bottom: 8px;
}
.radio-label {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  color: var(--text-dim);
  cursor: pointer;
  user-select: none;
}
.radio-label input[type="radio"] {
  accent-color: var(--accent);
  cursor: pointer;
}
.radio-label input[type="radio"]:disabled,
.input:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* ===== File upload ===== */
.upload-box {
  border: 1.5px dashed var(--border);
  border-radius: 8px;
  padding: 18px;
  text-align: center;
  cursor: pointer;
  transition: all 0.15s;
  background: var(--bg);
}
.upload-box:hover {
  border-color: var(--accent);
  background: rgba(56, 189, 248, 0.05);
}
.upload-box.drag {
  border-color: var(--accent);
  background: rgba(56, 189, 248, 0.1);
}
.upload-box .icon { font-size: 22px; margin-bottom: 6px; }
.upload-box .txt { font-size: 13px; color: var(--text-dim); }
.upload-box .hint { font-size: 11px; color: #64748b; margin-top: 4px; }
#eqeFile { display: none; }

.file-info {
  margin-top: 8px;
  font-size: 12px;
  color: var(--text-dim);
  padding: 6px 10px;
  background: var(--bg);
  border-radius: 6px;
  border: 1px solid var(--border);
}
.file-info.ok { color: #10b981; border-color: #10b98144; }
.file-info.err { color: #ef4444; border-color: #ef444444; }

.btn {
  width: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border: none;
  border-radius: 8px;
  padding: 12px;
  color: #0f172a;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.1s, opacity 0.15s;
  letter-spacing: 0.4px;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-sample {
  background: var(--panel-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  margin-top: 8px;
  font-weight: 500;
}

/* ===== Results ===== */
.results-panel { display: flex; flex-direction: column; gap: 20px; }

.kv-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}
@media (max-width: 640px) { .kv-grid { grid-template-columns: 1fr; } }

.kv-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px;
  border-left: 3px solid var(--accent);
}
.kv-card.v1 { border-left-color: var(--v1); }
.kv-card.v2 { border-left-color: var(--v2); }
.kv-card.v3 { border-left-color: var(--v3); }
.kv-card.voc { border-left-color: var(--voc); }
.kv-card.sq { border-left-color: var(--voc-sq); }

.kv-card .lbl {
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 4px;
}
.kv-card .val {
  font-size: 22px;
  font-weight: 700;
  font-family: 'JetBrains Mono', 'Consolas', monospace;
}
.kv-card .sub {
  font-size: 11px;
  color: #64748b;
  margin-top: 2px;
}

/* ===== Charts ===== */
.chart-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
}
.chart-card h3 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}
.chart-wrap { position: relative; height: 280px; }
.chart-wrap.tall { height: 340px; }

/* ===== Equation card ===== */
.eq-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
  margin-top: 20px;
}
.eq-card h3 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--accent);
}
.eq-list { display: flex; flex-direction: column; gap: 8px; }
.eq-item {
  font-size: 13px;
  color: var(--text-dim);
  padding: 8px 12px;
  background: var(--bg);
  border-radius: 6px;
  border-left: 2px solid var(--border);
}
.eq-item code {
  color: var(--text);
  font-family: 'JetBrains Mono', 'Consolas', monospace;
  font-size: 12px;
}
.eq-item .tag {
  display: inline-block;
  font-weight: 700;
  margin-right: 6px;
}
.eq-item .tag.v1 { color: var(--v1); }
.eq-item .tag.v2 { color: var(--v2); }
.eq-item .tag.v3 { color: var(--v3); }

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--panel-2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 13px;
  opacity: 0;
  pointer-events: none;
  transition: all 0.2s;
  z-index: 100;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.toast.err { border-color: var(--v3); color: #fecaca; }