/* ==========================================================================
   ذَرّة | ZARRA — pH Scale & Titration Lab Styles
   المرحلة 4: مقياس الرقم الهيدروجيني وتجربة المعايرة الكيميائية
   ========================================================================== */

.ph-spectrum-bar {
  height: 38px;
  border-radius: var(--radius-full);
  background: linear-gradient(90deg, 
    #D32F2F 0%,   /* pH 0 - أحمر قاني */
    #F57C00 20%,  /* pH 3 - برتقالي */
    #FBC02D 35%,  /* pH 5 - أصفر */
    #388E3C 50%,  /* pH 7 - أخضر متعادل */
    #0288D1 65%,  /* pH 9 - أزرق سماوي */
    #303F9F 80%,  /* pH 11 - أزرق داكن */
    #7B1FA2 100%  /* pH 14 - بنفسجي */
  );
  position: relative;
  box-shadow: var(--shadow-sm);
  margin: var(--spacing-lg) 0;
  cursor: pointer;
}

.ph-indicator-pin {
  position: absolute;
  top: -10px;
  transform: translateX(50%);
  width: 24px;
  height: 58px;
  border-radius: 6px;
  background: #fff;
  border: 3px solid var(--color-primary);
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 0.75rem;
  font-family: var(--font-chem-code);
  transition: left 0.3s ease;
}

.substance-chips-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: var(--spacing-md);
}

.substance-chip {
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius-full);
  background: var(--color-bg-surface-soft);
  border: 1px solid var(--color-border-soft);
  font-size: var(--font-size-xs);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all var(--transition-fast);
}

.substance-chip:hover,
.substance-chip.active {
  border-color: var(--color-primary);
  background: var(--color-primary-light);
  font-weight: 700;
  color: var(--color-primary);
}

/* منصة المعايرة بالسحاحة */
.titration-apparatus-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-xl);
  background: var(--color-bg-surface-soft);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border-soft);
  position: relative;
}

.burette-tube {
  width: 26px;
  height: 180px;
  border: 2px solid rgba(74, 48, 48, 0.4);
  border-bottom: none;
  background: rgba(255, 255, 255, 0.7);
  border-radius: 4px 4px 0 0;
  position: relative;
  overflow: hidden;
}

.burette-fluid-fill {
  position: absolute;
  bottom: 0;
  width: 100%;
  background: rgba(33, 150, 243, 0.45);
  transition: height 0.3s ease;
}

.burette-stopcock {
  width: 14px;
  height: 24px;
  background: var(--color-primary);
  border-radius: 2px;
  margin-bottom: 8px;
}

.flask-conical {
  width: 110px;
  height: 120px;
  clip-path: polygon(30% 0%, 70% 0%, 100% 100%, 0% 100%);
  border: 2px solid rgba(74, 48, 48, 0.4);
  background: rgba(255, 255, 255, 0.6);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: flex-end;
}

.flask-fluid-fill {
  width: 100%;
  height: 45%;
  background: rgba(255, 255, 255, 0.85);
  transition: all 0.4s ease;
}

/* منحنى المعايرة */
.titration-curve-box {
  background: var(--color-bg-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  margin-top: var(--spacing-lg);
}