/* ==========================================================================
   K-Weather Flow - Main Stylesheet
   Design Language: Ethereal Glassmorphism & Soft Structuralism
   ========================================================================== */

/* --- 1. Variables & Design Tokens --- */
:root {
  /* Common System Fonts */
  --font-display: 'Plus Jakarta Sans', 'Noto Sans KR', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Transitions */
  --transition-smooth: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-bounce: all 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Light Theme Tokens */
  --bg-app: #f4f4f7;
  --bg-orb-1: rgba(251, 191, 36, 0.15); /* sunny yellow */
  --bg-orb-2: rgba(59, 130, 246, 0.15);  /* rain blue */
  --bg-orb-3: rgba(244, 63, 94, 0.1);   /* coral red */
  
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  
  --bezel-outer-bg: rgba(0, 0, 0, 0.03);
  --bezel-outer-border: rgba(0, 0, 0, 0.04);
  --bezel-inner-bg: rgba(255, 255, 255, 0.75);
  --bezel-inner-border: rgba(255, 255, 255, 0.8);
  --bezel-inner-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.4), 0 8px 32px rgba(0, 0, 0, 0.04);
  
  --accent-color: #f43f5e;
  --btn-primary-bg: #1e293b;
  --btn-primary-text: #ffffff;
  --btn-secondary-bg: rgba(0, 0, 0, 0.05);
  --btn-secondary-text: #1e293b;
  
  /* Weather Gradients (Light) */
  --grad-clear: linear-gradient(135deg, rgba(251, 191, 36, 0.08) 0%, rgba(245, 158, 11, 0.02) 100%);
  --grad-clouds: linear-gradient(135deg, rgba(148, 163, 184, 0.08) 0%, rgba(100, 116, 139, 0.02) 100%);
  --grad-rain: linear-gradient(135deg, rgba(59, 130, 246, 0.08) 0%, rgba(37, 99, 235, 0.02) 100%);
  --grad-snow: linear-gradient(135deg, rgba(16, 185, 129, 0.08) 0%, rgba(5, 150, 105, 0.02) 100%);
}

html.dark {
  /* Dark Theme Tokens */
  --bg-app: #050505;
  --bg-orb-1: rgba(245, 158, 11, 0.1);
  --bg-orb-2: rgba(37, 99, 235, 0.1);
  --bg-orb-3: rgba(244, 63, 94, 0.08);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --bezel-outer-bg: rgba(255, 255, 255, 0.02);
  --bezel-outer-border: rgba(255, 255, 255, 0.04);
  --bezel-inner-bg: rgba(15, 23, 42, 0.45);
  --bezel-inner-border: rgba(255, 255, 255, 0.07);
  --bezel-inner-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.08), 0 12px 40px rgba(0, 0, 0, 0.5);
  
  --accent-color: #f43f5e;
  --btn-primary-bg: #f8fafc;
  --btn-primary-text: #0f172a;
  --btn-secondary-bg: rgba(255, 255, 255, 0.06);
  --btn-secondary-text: #f8fafc;
  
  /* Weather Gradients (Dark) */
  --grad-clear: linear-gradient(135deg, rgba(245, 158, 11, 0.12) 0%, rgba(251, 191, 36, 0.02) 100%);
  --grad-clouds: linear-gradient(135deg, rgba(148, 163, 184, 0.12) 0%, rgba(100, 116, 139, 0.02) 100%);
  --grad-rain: linear-gradient(135deg, rgba(59, 130, 246, 0.12) 0%, rgba(37, 99, 235, 0.02) 100%);
  --grad-snow: linear-gradient(135deg, rgba(16, 185, 129, 0.12) 0%, rgba(52, 211, 153, 0.02) 100%);
}

/* --- 2. Global Resets & Basics --- */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-display);
  background-color: var(--bg-app);
  color: var(--text-primary);
  min-height: 100dvh;
  position: relative;
  overflow-x: hidden;
  transition: background-color 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: opacity 0.2s ease;
}
a:hover {
  opacity: 0.8;
}

/* --- 3. Ambient Mesh Background Orbs --- */
.mesh-orbs {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  overflow: hidden;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(140px);
  will-change: transform;
  mix-blend-mode: normal;
  transition: background-color 0.8s ease;
}

.orb-1 {
  width: 50vw;
  height: 50vw;
  max-width: 600px;
  max-height: 600px;
  top: -10%;
  left: -10%;
  background-color: var(--bg-orb-1);
}

.orb-2 {
  width: 60vw;
  height: 60vw;
  max-width: 700px;
  max-height: 700px;
  bottom: -20%;
  right: -10%;
  background-color: var(--bg-orb-2);
}

.orb-3 {
  width: 40vw;
  height: 40vw;
  max-width: 500px;
  max-height: 500px;
  top: 40%;
  left: 40%;
  background-color: var(--bg-orb-3);
}

/* --- 4. Main App Layout Container --- */
.app-container {
  max-w: 1400px;
  width: 100%;
  margin: 0 auto;
  padding: 2.5rem 2rem 4rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

/* --- 5. Custom Typography & Layout Headers --- */
.eyebrow-tag {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.25em;
  color: var(--accent-color);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
}

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--bezel-outer-border);
}

.app-title {
  font-size: 2.75rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 0.35rem;
}

.app-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.control-area {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* --- 6. Double Bezel Design System (Doppelrand) --- */
.double-bezel-outer {
  background: var(--bezel-outer-bg);
  border: 1px solid var(--bezel-outer-border);
  border-radius: 1.75rem;
  padding: 0.375rem;
  transition: var(--transition-smooth);
}

.double-bezel-inner {
  background: var(--bezel-inner-bg);
  border: 1px solid var(--bezel-inner-border);
  box-shadow: var(--bezel-inner-shadow);
  border-radius: calc(1.75rem - 0.375rem);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  transition: var(--transition-smooth);
}

/* --- 7. Usage Process Section --- */
.usage-process-section {
  width: 100%;
}

.usage-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  align-items: center;
  padding: 1.5rem 2rem;
  gap: 1rem;
}

.usage-step {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.step-num {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-color);
  opacity: 0.75;
}

.step-info h4 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 0.15rem;
}

.step-info p {
  font-size: 0.75rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.usage-step-arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
}
.usage-step-arrow svg {
  width: 1.25rem;
  height: 1.25rem;
}

/* --- 8. Summary Widget Section --- */
.summary-widget-section {
  width: 100%;
}

.summary-container {
  display: grid;
  grid-template-columns: repeat(3, 1fr) auto;
  align-items: center;
  padding: 1.25rem 2rem;
  gap: 2rem;
}

.summary-item {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  border-right: 1px solid var(--bezel-outer-border);
  padding-right: 2rem;
}
.summary-item:nth-child(3) {
  border-right: none;
}

.summary-item .label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.summary-item .value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.summary-action {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.35rem;
}

.update-time {
  font-size: 0.7rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* --- 9. Weather Dashboard Cards Grid --- */
.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1.5rem;
  width: 100%;
}

/* Card Bezel Specifics */
.weather-card-wrapper {
  cursor: pointer;
  perspective: 1000px;
}

.weather-card-wrapper:hover .double-bezel-outer {
  transform: translateY(-4px);
  border-color: rgba(244, 63, 94, 0.15);
}

.weather-card-wrapper:active .double-bezel-outer {
  transform: translateY(-1px) scale(0.98);
}

.weather-card {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  height: 180px;
  position: relative;
  overflow: hidden;
  background-origin: border-box;
}

/* Weather Condition Gradient Applications */
.weather-card[data-weather="clear"] { background: var(--grad-clear); }
.weather-card[data-weather="clouds"] { background: var(--grad-clouds); }
.weather-card[data-weather="rain"] { background: var(--grad-rain); }
.weather-card[data-weather="snow"] { background: var(--grad-snow); }

.card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  z-index: 2;
}

.city-names {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.city-ko {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.city-en {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.weather-icon-wrap {
  width: 2.75rem;
  height: 2.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(8px);
}
.weather-icon-wrap svg {
  width: 1.75rem;
  height: 1.75rem;
}

.card-bottom {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  z-index: 2;
}

.temp-display {
  display: flex;
  align-items: flex-start;
}

.temp-val {
  font-family: var(--font-mono);
  font-size: 2.5rem;
  font-weight: 600;
  line-height: 0.9;
  letter-spacing: -0.05em;
}

.temp-unit {
  font-size: 1.1rem;
  font-weight: 500;
  margin-top: 0.1rem;
  margin-left: 0.15rem;
}

.weather-status {
  text-align: right;
}

.status-desc {
  font-size: 0.85rem;
  font-weight: 600;
}

.status-range {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-secondary);
  margin-top: 0.2rem;
}

/* --- 10. Buttons & Interactive States --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.65rem 1.25rem;
  border-radius: 2rem;
  border: none;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.btn-primary {
  background: var(--btn-primary-bg);
  color: var(--btn-primary-text);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.12);
}
.btn-primary:active {
  transform: translateY(-0.5px) scale(0.98);
}

.btn-secondary {
  background: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border: 1px solid var(--bezel-outer-border);
}
.btn-secondary:hover {
  background: rgba(0,0,0,0.08);
  transform: translateY(-2px);
}
html.dark .btn-secondary:hover {
  background: rgba(255,255,255,0.1);
}
.btn-secondary:active {
  transform: translateY(-0.5px) scale(0.98);
}

.btn-icon-round {
  width: 2.35rem;
  height: 2.35rem;
  padding: 0;
  border-radius: 50%;
  background: var(--btn-secondary-bg);
  border: 1px solid var(--bezel-outer-border);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-bounce);
}
.btn-icon-round:hover {
  transform: scale(1.1) rotate(15deg);
}

.btn-link {
  background: transparent;
  color: var(--text-secondary);
  padding: 0.5rem 1rem;
}
.btn-link:hover {
  color: var(--text-primary);
  text-decoration: underline;
}

.icon {
  width: 1.1rem;
  height: 1.1rem;
}

.icon-spin-hover:hover {
  animation: spin 1s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* Theme Switching Icons */
.sun-icon { display: none; }
.moon-icon { display: block; }
html.dark .sun-icon { display: block; }
html.dark .moon-icon { display: none; }

/* --- 11. Custom Skeleton Loaders --- */
.card-skeleton {
  height: 180px;
  background: var(--bezel-outer-bg);
  border: 1px solid var(--bezel-outer-border);
  border-radius: 1.75rem;
  position: relative;
  overflow: hidden;
}

.card-skeleton::after {
  content: "";
  position: absolute;
  top: 0; right: 0; bottom: 0; left: 0;
  transform: translateX(-100%);
  background: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0) 0%,
    rgba(255, 255, 255, 0.05) 20%,
    rgba(255, 255, 255, 0.1) 60%,
    rgba(255, 255, 255, 0) 100__
  );
  animation: shimmer 2s infinite;
}

html.dark .card-skeleton::after {
  background: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0) 0%,
    rgba(255, 255, 255, 0.02) 20%,
    rgba(255, 255, 255, 0.05) 60%,
    rgba(255, 255, 255, 0) 100%
  );
}

.loading-shimmer {
  position: relative;
  overflow: hidden;
}
.loading-shimmer::after {
  content: "";
  position: absolute;
  top: 0; right: 0; bottom: 0; left: 0;
  transform: translateX(-100%);
  background: linear-gradient(90deg, transparent 0%, rgba(255,255,255,0.05) 50%, transparent 100%);
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  100% { transform: translateX(100%); }
}

/* --- 12. Modal Overlay & Cards (Popup Layer) --- */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  padding: 1.5rem;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-container {
  width: 100%;
  max-width: 580px;
  transform: scale(0.9) translateY(20px);
  transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.modal-overlay.active .modal-container {
  transform: scale(1) translateY(0);
}

.modal-content {
  position: relative;
  padding: 2.5rem;
}

.modal-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  border: 1px solid var(--bezel-outer-border);
  background: var(--btn-secondary-bg);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
}
.modal-close:hover {
  transform: scale(1.1) rotate(90deg);
}

/* Modal Detailed Contents Styling */
.weather-detail-modal {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.modal-header-section {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  border-bottom: 1px solid var(--bezel-outer-border);
  padding-bottom: 1rem;
}

.modal-title h2 {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
}

.modal-title p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.modal-temp-box {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
}

.modal-temp-main {
  font-family: var(--font-mono);
  font-size: 3.5rem;
  font-weight: 600;
  line-height: 1;
}

.modal-weather-desc {
  font-size: 1rem;
  font-weight: 600;
  margin-top: 0.25rem;
  color: var(--accent-color);
}

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

.metric-card-outer {
  background: var(--bezel-outer-bg);
  border: 1px solid var(--bezel-outer-border);
  border-radius: 1.25rem;
  padding: 0.25rem;
}

.metric-card-inner {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: calc(1.25rem - 0.25rem);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.metric-icon-wrap {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-color);
}
.metric-icon-wrap svg {
  width: 1.25rem;
  height: 1.25rem;
}

.metric-data {
  display: flex;
  flex-direction: column;
}

.metric-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.metric-value {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  margin-top: 0.15rem;
}

/* --- 13. Step-by-Step Tutorial System --- */
.tutorial-overlay {
  background: rgba(0, 0, 0, 0.6);
  z-index: 200;
}

.tutorial-container {
  width: 100%;
  max-width: 480px;
  transform: scale(0.9) translateY(20px);
  transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.tutorial-overlay.active .tutorial-container {
  transform: scale(1) translateY(0);
}

.tutorial-content {
  padding: 2.25rem;
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.tutorial-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--bezel-outer-border);
  padding-bottom: 0.75rem;
}

.step-indicator {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.tutorial-body {
  position: relative;
  min-height: 220px;
}

.tutorial-slide {
  display: none;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 1rem;
  animation: slideFadeIn 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

.tutorial-slide.active {
  display: flex;
}

@keyframes slideFadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.tut-visual {
  width: 4.5rem;
  height: 4.5rem;
  border-radius: 1.25rem;
  background: var(--bezel-outer-bg);
  border: 1px solid var(--bezel-outer-border);
  color: var(--accent-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 0.5rem;
}
.tut-visual svg {
  width: 2.5rem;
  height: 2.5rem;
}

.tutorial-slide h3 {
  font-size: 1.25rem;
  font-weight: 700;
}

.tutorial-slide p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
  max-w: 32ch;
}

.tutorial-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--bezel-outer-border);
  padding-top: 1rem;
}

.nav-buttons {
  display: flex;
  gap: 0.5rem;
}

/* --- 14. Responsive Footer (FLOW Research Brand) --- */
.app-footer {
  border-top: 1px solid var(--bezel-outer-border);
  padding-top: 3rem;
  margin-top: 2rem;
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.65rem;
}

.developed-by {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  text-transform: uppercase;
}

.author {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.company-logo {
  display: inline-block;
  background: var(--bezel-outer-bg);
  border: 1px solid var(--bezel-outer-border);
  border-radius: 0.5rem;
  padding: 0.35rem 0.85rem;
  margin-bottom: 0.25rem;
}

.company-name {
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  color: var(--text-primary);
}

.slogan {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.homepage {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.copyright {
  font-size: 0.65rem;
  color: var(--text-muted);
  margin-top: 1.5rem;
  letter-spacing: 0.02em;
}

/* --- 15. Responsive Breakpoints --- */

/* Desktop & Large Screen Adjustments */
@media (max-width: 1400px) {
  .app-container {
    max-width: 100%;
    padding: 2rem 1.5rem;
  }
}

/* Laptop (1024px ~ 1280px) */
@media (max-width: 1280px) {
  .dashboard-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* Tablet (768px ~ 1024px) */
@media (max-width: 1024px) {
  .dashboard-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .usage-grid {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }
  .usage-step-arrow {
    transform: rotate(90deg);
    margin: 0.25rem 0;
  }
  .summary-container {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
  }
  .summary-item:nth-child(2) {
    border-right: none;
  }
  .summary-action {
    grid-column: span 2;
    align-items: center;
    border-top: 1px solid var(--bezel-outer-border);
    padding-top: 1rem;
  }
}

/* Mobile Devices (< 768px) */
@media (max-width: 768px) {
  .app-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.25rem;
  }
  .control-area {
    width: 100%;
    justify-content: space-between;
  }
  .dashboard-grid {
    grid-template-columns: 1fr; /* Aggressive mobile collapse to single-col */
    gap: 1.25rem;
  }
  .summary-container {
    grid-template-columns: 1fr;
    padding: 1.25rem;
  }
  .summary-item {
    border-right: none;
    border-bottom: 1px solid var(--bezel-outer-border);
    padding-bottom: 1rem;
    padding-right: 0;
  }
  .summary-action {
    grid-column: span 1;
  }
  .app-title {
    font-size: 2.25rem;
  }
  .usage-step-arrow {
    display: none; /* Hide helper arrows on mobile vertical stack */
  }
  .modal-container {
    padding: 0.5rem;
  }
  .modal-content {
    padding: 1.5rem;
  }
  .modal-metrics-grid {
    grid-template-columns: 1fr; /* Stack detail cards on mobile */
  }
}