/* ═══════════════════════════════════════════════════════════════
   Student Performance Survey — Stylesheet
   ═══════════════════════════════════════════════════════════════ */

/* ── Custom Properties ── */
:root {
  --primary:       #1e3a5f;
  --primary-hover: #16304f;
  --accent:        #3b82f6;
  --accent-light:  #dbeafe;
  --accent-dark:   #1d4ed8;
  --success:       #16a34a;
  --success-light: #dcfce7;
  --error:         #dc2626;
  --error-light:   #fee2e2;
  --warning:       #d97706;
  --bg:            #f1f5f9;
  --card:          #ffffff;
  --border:        #e2e8f0;
  --border-focus:  #3b82f6;
  --text:          #1e293b;
  --text-muted:    #64748b;
  --text-light:    #94a3b8;
  --radius:        12px;
  --radius-sm:     8px;
  --shadow:        0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
  --shadow-md:     0 4px 6px rgba(0,0,0,.07), 0 10px 30px rgba(0,0,0,.10);
  --transition:    0.18s ease;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; color: var(--accent-dark); }

ul { padding-left: 1.4rem; }
li { margin-bottom: 0.4rem; }

/* ═══════════════════════════════════════════════════════════════
   HEADER
   ═══════════════════════════════════════════════════════════════ */
.site-header {
  background: linear-gradient(135deg, var(--primary) 0%, #2c5282 100%);
  color: #fff;
  padding: 1.75rem 1.5rem;
  box-shadow: 0 2px 12px rgba(0,0,0,.2);
}

.header-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.header-icon { font-size: 2.5rem; line-height: 1; }

.header-text h1 {
  font-size: 1.65rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.header-text p {
  font-size: 0.9rem;
  opacity: 0.8;
  margin-top: 0.2rem;
}

/* ═══════════════════════════════════════════════════════════════
   TAB NAVIGATION
   ═══════════════════════════════════════════════════════════════ */
.tab-nav {
  background: var(--primary);
  border-bottom: 3px solid rgba(255,255,255,0.12);
  position: sticky;
  top: 0;
  z-index: 100;
}

.tab-nav-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  gap: 0;
}

.tab-btn {
  background: transparent;
  border: none;
  color: rgba(255,255,255,0.65);
  padding: 0.9rem 1.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: var(--transition);
  border-bottom: 3px solid transparent;
  margin-bottom: -3px;
  white-space: nowrap;
}

.tab-btn:hover { color: rgba(255,255,255,0.9); background: rgba(255,255,255,0.06); }

.tab-btn.active {
  color: #fff;
  border-bottom-color: #60a5fa;
  background: rgba(255,255,255,0.08);
}

/* ═══════════════════════════════════════════════════════════════
   MAIN CONTENT & TAB PANELS
   ═══════════════════════════════════════════════════════════════ */
.main-content {
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  flex: 1;
  width: 100%;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.panel-intro {
  margin-bottom: 2rem;
}

.panel-intro h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.4rem;
}

.panel-intro p { color: var(--text-muted); max-width: 620px; }

/* ═══════════════════════════════════════════════════════════════
   FORM SECTIONS
   ═══════════════════════════════════════════════════════════════ */
.form-section {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow);
}

.section-header {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.section-num {
  background: var(--primary);
  color: #fff;
  width: 2.1rem;
  height: 2.1rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.section-header h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.15rem;
}

.section-header p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ── Grid Layouts ── */
.form-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.form-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

/* ── Form Group ── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  margin-bottom: 1.25rem;
}

.form-group:last-child { margin-bottom: 0; }

.field-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.attr-tag {
  display: none;
}

.field-hint {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 0.1rem;
}

.subsection-label {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-muted);
  margin: 1.25rem 0 0.75rem;
}

/* ── Inputs & Selects ── */
input[type="number"],
select {
  padding: 0.6rem 0.85rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  color: var(--text);
  background: #fff;
  transition: var(--transition);
  width: 100%;
  appearance: none;
  -webkit-appearance: none;
}

select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  padding-right: 2.25rem;
}

input[type="number"]:focus,
select:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.15);
}

input.field-error, select.field-error {
  border-color: var(--error);
  box-shadow: 0 0 0 3px rgba(220,38,38,0.12);
}

/* ── Radio Cards ── */
.radio-card-group {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.radio-card-group.col { flex-direction: column; }

.radio-card { display: flex; cursor: pointer; }

.radio-card input[type="radio"] { display: none; }

.rc-box {
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.6rem 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.2rem;
  transition: var(--transition);
  min-width: 80px;
  text-align: center;
  background: #fff;
  user-select: none;
}

.rc-box strong { font-size: 0.9rem; color: var(--text); }
.rc-box small  { font-size: 0.72rem; color: var(--text-muted); }

.radio-card input:checked + .rc-box {
  border-color: var(--accent);
  background: var(--accent-light);
}

.radio-card input:checked + .rc-box strong { color: var(--accent-dark); }
.radio-card input:checked + .rc-box small  { color: var(--accent); }

.radio-card:hover .rc-box {
  border-color: #93c5fd;
  background: #f0f7ff;
}

.radio-card-group.error-group .rc-box { border-color: var(--error); }

/* ── Scale Buttons ── */
.scale-buttons {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.scale-btn {
  flex: 1;
  min-width: 60px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  padding: 0.6rem 0.4rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  background: #fff;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  transition: var(--transition);
  line-height: 1;
}

.scale-btn span {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text);
  text-align: center;
  line-height: 1.2;
}

.scale-btn:hover {
  border-color: #93c5fd;
  background: #f0f7ff;
  color: var(--accent-dark);
}

.scale-btn.active {
  background: var(--accent);
  border-color: var(--accent-dark);
  color: #fff;
}

.scale-btn.active span { color: rgba(255,255,255,0.85); }

.scale-buttons.error-group .scale-btn { border-color: var(--error); }

/* ── Yes / No Grid ── */
.yn-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

.yn-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.85rem 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.yn-label {
  font-size: 0.83rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
  flex: 1;
}

.yn-btns {
  display: flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.yn-opt {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.85rem;
  cursor: pointer;
  color: var(--text);
  font-weight: 500;
  white-space: nowrap;
}

.yn-opt input[type="radio"] { accent-color: var(--accent); width: 15px; height: 15px; cursor: pointer; }

.yn-item.error-group { border-color: var(--error); background: var(--error-light); }

/* ── Form Actions ── */
.form-actions {
  display: flex;
  gap: 1rem;
  align-items: center;
  margin-top: 2rem;
  flex-wrap: wrap;
}

.btn-submit {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 0.85rem 2.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 2px 8px rgba(30,58,95,0.3);
}

.btn-submit:hover { background: var(--primary-hover); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(30,58,95,0.35); }
.btn-submit:active { transform: translateY(0); }
.btn-submit:disabled { opacity: 0.6; cursor: not-allowed; transform: none; }

.btn-reset {
  background: transparent;
  border: 1.5px solid var(--border);
  color: var(--text-muted);
  padding: 0.85rem 1.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.btn-reset:hover { border-color: var(--error); color: var(--error); background: var(--error-light); }

/* ── Form Feedback ── */
.form-feedback {
  margin-top: 1.25rem;
  padding: 1rem 1.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1.5;
}

.form-feedback.success {
  background: var(--success-light);
  border: 1.5px solid #bbf7d0;
  color: #15803d;
}

.form-feedback.error {
  background: var(--error-light);
  border: 1.5px solid #fecaca;
  color: var(--error);
}

/* ── Error summary ── */
.error-summary {
  background: var(--error-light);
  border: 1.5px solid #fecaca;
  border-radius: var(--radius-sm);
  padding: 0.9rem 1.1rem;
  margin-bottom: 1.5rem;
  font-size: 0.85rem;
  color: var(--error);
}

.error-summary p { font-weight: 600; margin-bottom: 0.4rem; }
.error-summary ul { margin: 0; }

/* ═══════════════════════════════════════════════════════════════
   ABOUT TAB
   ═══════════════════════════════════════════════════════════════ */
.about-hero {
  background: linear-gradient(135deg, var(--primary) 0%, #2c5282 100%);
  color: #fff;
  padding: 2.25rem 2rem;
  border-radius: var(--radius);
  margin-bottom: 1.75rem;
  box-shadow: var(--shadow-md);
}

.about-hero h2 { font-size: 1.6rem; font-weight: 700; margin-bottom: 0.5rem; }
.about-hero p  { opacity: 0.85; font-size: 0.95rem; max-width: 580px; }

.about-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.about-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: var(--shadow);
}

.about-card.full-width { grid-column: 1 / -1; }

.about-icon {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

.about-card h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.75rem;
}

.about-card p  { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 0.75rem; }
.about-card p:last-child { margin-bottom: 0; }
.about-card ul { color: var(--text-muted); font-size: 0.9rem; }
.about-card li { margin-bottom: 0.5rem; }
.about-card strong { color: var(--text); }
.about-card code  {
  font-family: 'Menlo', 'Consolas', monospace;
  font-size: 0.82rem;
  background: var(--bg);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  border: 1px solid var(--border);
}

blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.75rem 1rem;
  margin: 0.75rem 0;
  background: var(--bg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.author-card { background: linear-gradient(135deg, #f0f7ff 0%, #fff 100%); }

.author-details {
  margin-bottom: 1.25rem;
}

.author-name {
  font-size: 1.05rem !important;
  font-weight: 700 !important;
  color: var(--primary) !important;
}

.license-box {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.9rem 1rem;
}

.license-badge {
  display: inline-block;
  background: var(--success-light);
  color: var(--success);
  border: 1px solid #bbf7d0;
  border-radius: 20px;
  padding: 0.25rem 0.75rem;
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

/* ═══════════════════════════════════════════════════════════════
   SETUP TAB
   ═══════════════════════════════════════════════════════════════ */
.steps-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.step-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
}

.step-num {
  background: var(--primary);
  color: #fff;
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
}

.step-body { flex: 1; }

.step-body h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.6rem;
}

.step-body p  { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 0.75rem; }
.step-body p:last-child { margin-bottom: 0; }
.step-body ol { color: var(--text-muted); font-size: 0.9rem; padding-left: 1.3rem; }
.step-body li { margin-bottom: 0.4rem; }
.step-body strong { color: var(--text); }
.step-body code {
  font-family: 'Menlo', 'Consolas', monospace;
  font-size: 0.82rem;
  background: var(--bg);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  border: 1px solid var(--border);
}

/* ── Code Block ── */
.code-block {
  background: #0f172a;
  border-radius: var(--radius-sm);
  margin: 0.9rem 0;
  overflow: hidden;
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.6rem 1rem;
  background: #1e293b;
  border-bottom: 1px solid #334155;
}

.code-header span {
  color: #94a3b8;
  font-size: 0.78rem;
  font-family: 'Menlo', 'Consolas', monospace;
}

.copy-btn {
  background: #334155;
  color: #94a3b8;
  border: none;
  padding: 0.25rem 0.7rem;
  border-radius: 4px;
  font-size: 0.75rem;
  cursor: pointer;
  transition: var(--transition);
}

.copy-btn:hover { background: #475569; color: #e2e8f0; }
.copy-btn.copied { background: #16a34a; color: #fff; }

.code-block pre {
  color: #e2e8f0;
  font-family: 'Menlo', 'Consolas', 'Courier New', monospace;
  font-size: 0.8rem;
  line-height: 1.7;
  padding: 1.1rem 1.25rem;
  overflow-x: auto;
  white-space: pre;
}

/* ═══════════════════════════════════════════════════════════════
   FOOTER
   ═══════════════════════════════════════════════════════════════ */
.site-footer {
  background: var(--primary);
  color: rgba(255,255,255,0.7);
  padding: 1.5rem;
  margin-top: auto;
}

.footer-inner {
  max-width: 960px;
  margin: 0 auto;
  text-align: center;
  font-size: 0.83rem;
  line-height: 1.7;
}

.footer-inner p + p { margin-top: 0.25rem; }
.footer-inner a { color: #93c5fd; }
.footer-inner a:hover { color: #bfdbfe; }
.footer-inner strong { color: #fff; }

/* ═══════════════════════════════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════════════════════════════ */
@media (max-width: 700px) {
  .header-text h1 { font-size: 1.25rem; }
  .tab-btn { padding: 0.75rem 1rem; font-size: 0.82rem; }
  .main-content { padding: 1.25rem 1rem; }
  .form-section { padding: 1.25rem; }
  .form-grid-2, .form-grid-3 { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .about-card.full-width { grid-column: 1; }
  .yn-grid { grid-template-columns: 1fr; }
  .step-card { flex-direction: column; gap: 0.75rem; }
  .scale-btn { min-width: 50px; font-size: 0.9rem; }
  .form-actions { flex-direction: column; }
  .btn-submit, .btn-reset { width: 100%; text-align: center; }
}