.stc-app {
  width: min(980px, 100%);
  margin: 0 auto;
  background: #ffffff;
  border-radius: 18px;
  box-shadow: 0 18px 45px rgba(15, 23, 42, 0.12);
  padding: 28px;
  border: 1px solid rgba(219, 227, 239, 0.75);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #0f172a;
}

.stc-hero {
  border: 1px solid #b9d3ff;
  background: linear-gradient(135deg, #eef6ff, #f8fbff);
  border-radius: 12px;
  padding: 22px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 18px;
  margin-bottom: 26px;
}

.stc-hero span {
  display: block;
  color: #1f4ed8;
  font-size: 1rem;
  font-weight: 800;
  margin-bottom: 4px;
}

.stc-current-time {
  font-size: clamp(2rem, 5vw, 3.2rem);
  line-height: 1;
  color: #173da6;
  font-weight: 900;
  letter-spacing: -0.05em;
}

.stc-current-date {
  margin-top: 8px;
  color: #1f4ed8;
  font-weight: 700;
}

.stc-clock {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  border: 5px solid #2f6be6;
  flex: 0 0 auto;
  position: relative;
}

.stc-clock::before,
.stc-clock::after {
  content: "";
  position: absolute;
  background: #2f6be6;
  border-radius: 99px;
  left: 31px;
  top: 18px;
  transform-origin: bottom center;
}

.stc-clock::before {
  width: 5px;
  height: 21px;
}

.stc-clock::after {
  width: 5px;
  height: 16px;
  transform: rotate(90deg) translateY(-8px);
}

.stc-heading {
  font-size: clamp(1.7rem, 4vw, 2.35rem);
  letter-spacing: -0.04em;
  margin: 0 0 8px;
}

.stc-subtitle {
  color: #64748b;
  margin-bottom: 24px;
  line-height: 1.6;
  max-width: 760px;
}

.stc-section-title {
  font-size: 1.05rem;
  margin-bottom: 14px;
  font-weight: 850;
}

.stc-chips {
  display: grid;
  grid-template-columns: repeat(5, minmax(120px, 1fr));
  gap: 12px;
  margin-bottom: 26px;
}

.stc-chip {
  border: 0;
  border-radius: 10px;
  background: #f4f6fa;
  color: #0b172d;
  font-weight: 800;
  padding: 13px 12px;
  cursor: pointer;
  transition: 0.2s ease;
}

.stc-chip:hover {
  background: #e8eef8;
  transform: translateY(-1px);
}

.stc-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 16px;
}

.stc-field label {
  display: block;
  color: #20304b;
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.stc-field input,
.stc-field select {
  width: 100%;
  min-height: 52px;
  border-radius: 10px;
  border: 1px solid #dbe3ef;
  background: #ffffff;
  color: #0f172a;
  font-size: 1rem;
  padding: 0 14px;
  outline: none;
}

.stc-field input:focus,
.stc-field select:focus {
  border-color: #7aa7ff;
  box-shadow: 0 0 0 4px rgba(47, 107, 230, 0.12);
}

.stc-actions {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 12px;
  margin: 18px 0 24px;
}

.stc-btn {
  min-height: 54px;
  border: 0;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 900;
  cursor: pointer;
  transition: 0.2s ease;
}

.stc-main {
  background: #ff5a1f;
  color: #ffffff;
}

.stc-main:hover {
  background: #e64a12;
  transform: translateY(-1px);
}

.stc-clear {
  background: #e5e8ee;
  color: #111827;
}

.stc-clear:hover {
  background: #d9dee8;
  transform: translateY(-1px);
}

.stc-copy {
  background: #dbeafe;
  color: #1d4ed8;
}

.stc-copy:hover {
  background: #c7ddff;
  transform: translateY(-1px);
}

.stc-result {
  display: none;
  border: 1px solid #a7f3d0;
  background: #ecfdf5;
  border-radius: 12px;
  padding: 20px;
  color: #064e3b;
}

.stc-result.show {
  display: block;
}

.stc-result h3 {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.stc-result-main {
  font-size: clamp(1.35rem, 3vw, 1.9rem);
  font-weight: 950;
  letter-spacing: -0.04em;
  margin-bottom: 8px;
}

.stc-result p {
  color: #047857;
  line-height: 1.55;
  font-weight: 650;
}

.stc-helper {
  background: #f8fafc;
  border: 1px solid #dbe3ef;
  border-radius: 12px;
  padding: 16px;
  color: #64748b;
  line-height: 1.6;
  margin-top: 18px;
}

.stc-error {
  display: none;
  margin: -4px 0 16px;
  color: #b91c1c;
  background: #fef2f2;
  border: 1px solid #fecaca;
  padding: 12px 14px;
  border-radius: 10px;
  font-weight: 700;
}

.stc-error.show {
  display: block;
}

.stc-hidden {
  display: none;
}

@media (max-width: 820px) {
  .stc-app {
    padding: 18px;
  }

  .stc-chips {
    grid-template-columns: repeat(2, 1fr);
  }

  .stc-grid,
  .stc-actions {
    grid-template-columns: 1fr;
  }

  .stc-hero {
    align-items: flex-start;
  }

  .stc-clock {
    width: 58px;
    height: 58px;
    border-width: 4px;
  }
}

@media (max-width: 440px) {
  .stc-chips {
    grid-template-columns: 1fr;
  }

  .stc-clock {
    display: none;
  }
}