/*
  -----------------------------------------------------------
  Copyright (c) 2026 Ahngunism. All rights reserved.
  -----------------------------------------------------------
  File           : style.css
  Last updated:  : 20260401 090700
  Version        : ver 2
  -----------------------------------------------------------
*/

/* ═══════════════════ CSS VARIABLES ═══════════════════ */
:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 350ms cubic-bezier(0.22, 1, 0.36, 1);

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.16);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
}

/* ═══════════════════ DARK THEME (Default) ═══════════════════ */
[data-theme="dark"] {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a2e;
  --bg-panel: #13131f;
  --bg-panel-hover: #1a1a2e;
  --bg-input: #0d0d16;

  --text-primary: #e8e8f0;
  --text-secondary: #9898b0;
  --text-tertiary: #5a5a78;
  --text-muted: #3a3a50;

  --border-color: #2a2a40;
  --border-hover: #3a3a58;
  --border-focus: #6366f1;

  --accent-primary: #6366f1;
  --accent-primary-hover: #818cf8;
  --accent-secondary: #a78bfa;
  --accent-gradient: linear-gradient(135deg, #6366f1, #8b5cf6, #a78bfa);
  --accent-gradient-hover: linear-gradient(135deg, #818cf8, #a78bfa, #c4b5fd);

  --success: #34d399;
  --success-bg: rgba(52, 211, 153, 0.1);
  --error: #f87171;
  --error-bg: rgba(248, 113, 113, 0.1);
  --warning: #fbbf24;

  --glass-bg: rgba(19, 19, 31, 0.8);
  --glass-border: rgba(255, 255, 255, 0.06);
  --glass-blur: blur(20px);

  --scrollbar-track: #12121a;
  --scrollbar-thumb: #2a2a40;
}

/* ═══════════════════ LIGHT THEME ═══════════════════ */
[data-theme="light"] {
  --bg-primary: #f5f5fa;
  --bg-secondary: #ffffff;
  --bg-tertiary: #eeeef5;
  --bg-panel: #ffffff;
  --bg-panel-hover: #f8f8fc;
  --bg-input: #f0f0f6;

  --text-primary: #1a1a2e;
  --text-secondary: #5a5a78;
  --text-tertiary: #9898b0;
  --text-muted: #c0c0d0;

  --border-color: #e0e0ea;
  --border-hover: #c0c0d0;
  --border-focus: #6366f1;

  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-secondary: #7c3aed;
  --accent-gradient: linear-gradient(135deg, #6366f1, #7c3aed, #8b5cf6);
  --accent-gradient-hover: linear-gradient(135deg, #4f46e5, #6d28d9, #7c3aed);

  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.1);
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.1);
  --warning: #f59e0b;

  --glass-bg: rgba(255, 255, 255, 0.85);
  --glass-border: rgba(0, 0, 0, 0.06);
  --glass-blur: blur(20px);

  --scrollbar-track: #f0f0f6;
  --scrollbar-thumb: #d0d0da;
}

/* ═══════════════════ RESET & BASE ═══════════════════ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background var(--transition-base), color var(--transition-base);
  overflow-x: hidden;
}

/* Custom scrollbar */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--scrollbar-track); }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: var(--radius-full); }
::-webkit-scrollbar-thumb:hover { background: var(--border-hover); }

/* ═══════════════════ HEADER ═══════════════════ */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid var(--glass-border);
}

.header__inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--space-md) var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header__brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header__logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header__title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header__controls {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

/* ═══════════════════ LANGUAGE SELECTOR ═══════════════════ */
.lang-selector {
  position: relative;
}

.lang-selector__btn {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.lang-selector__btn:hover {
  border-color: var(--border-hover);
  background: var(--bg-panel-hover);
}

.lang-selector__chevron {
  transition: transform var(--transition-fast);
}

.lang-selector.open .lang-selector__chevron {
  transform: rotate(180deg);
}

.lang-selector__dropdown {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 160px;
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: var(--space-xs);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px) scale(0.96);
  transition: all var(--transition-fast);
  z-index: 200;
}

.lang-selector.open .lang-selector__dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.lang-option {
  display: block;
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  text-align: left;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.lang-option:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.lang-option.active {
  background: var(--accent-primary);
  color: #fff;
}

/* ═══════════════════ THEME TOGGLE ═══════════════════ */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 1.1rem;
}

.theme-toggle:hover {
  border-color: var(--border-hover);
  background: var(--bg-panel-hover);
  transform: scale(1.05);
}

/* ═══════════════════ MAIN ═══════════════════ */
.main {
  flex: 1;
  max-width: 1400px;
  width: 100%;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

/* ═══════════════════ CONVERTER LAYOUT ═══════════════════ */
.converter {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 0;
  align-items: stretch;
  min-height: 420px;
}

/* ═══════════════════ PANELS ═══════════════════ */
.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  overflow: hidden;
}

.panel:focus-within {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--border-color);
}

.panel__label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
}

.panel__actions {
  display: flex;
  gap: var(--space-xs);
}

.panel__action-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: none;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--text-tertiary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.panel__action-btn:hover {
  background: var(--bg-tertiary);
  border-color: var(--border-color);
  color: var(--text-primary);
}

.panel__action-btn.copied {
  color: var(--success);
  background: var(--success-bg);
}

.panel__textarea {
  flex: 1;
  width: 100%;
  padding: var(--space-lg);
  background: transparent;
  border: none;
  outline: none;
  resize: none;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--text-primary);
  min-height: 320px;
}

.panel__textarea::placeholder {
  color: var(--text-muted);
}

.panel__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-lg);
  border-top: 1px solid var(--border-color);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
}

/* ═══════════════════ CENTER BAR ═══════════════════ */
.center-bar {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
  padding: var(--space-lg) var(--space-md);
  min-width: 80px;
}

.center-bar__arrow-group {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
}

.center-bar__arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  opacity: 0.3;
  color: var(--text-tertiary);
}

.center-bar__arrow.active {
  opacity: 1;
  color: var(--accent-primary);
}

.center-bar__arrow.active.center-bar__arrow--right {
  animation: pulseRight 1.8s ease-in-out infinite;
}

.center-bar__arrow.active.center-bar__arrow--left {
  animation: pulseLeft 1.8s ease-in-out infinite;
}

@keyframes pulseRight {
  0%, 100% { opacity: 1; transform: translateX(0); }
  50% { opacity: 0.7; transform: translateX(3px); }
}

@keyframes pulseLeft {
  0%, 100% { opacity: 1; transform: translateX(0); }
  50% { opacity: 0.7; transform: translateX(-3px); }
}

.center-bar__arrow-label {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.center-bar__swap-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-tertiary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.center-bar__swap-btn:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  background: rgba(99, 102, 241, 0.1);
}

/* ═══════════════════ STATUS BAR ═══════════════════ */
.status-bar {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  margin-top: var(--space-md);
  border-radius: var(--radius-md);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  transition: all var(--transition-fast);
  min-height: 38px;
}

.status-bar.success {
  background: var(--success-bg);
  border-color: var(--success);
  color: var(--success);
}

.status-bar.error {
  background: var(--error-bg);
  border-color: var(--error);
  color: var(--error);
}

/* ═══════════════════ INFO CARDS ═══════════════════ */
.info-section {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

.info-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-align: center;
  transition: all var(--transition-base);
}

.info-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.info-card__icon {
  font-size: 2rem;
  margin-bottom: var(--space-md);
}

.info-card__title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.info-card__desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ═══════════════════ AD SECTION ═══════════════════ */
.ad-section {
  margin-top: var(--space-2xl);
}

.ad-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  max-width: 700px;
  margin: 0 auto;
}

.ad-slot {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60px;
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--space-sm);
  overflow: hidden;
}

/* ═══════════════════ FOOTER ═══════════════════ */
.footer {
  text-align: center;
  padding: var(--space-xl) var(--space-lg);
  border-top: 1px solid var(--border-color);
}

.footer__text {
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

/* ═══════════════════ TOAST NOTIFICATION ═══════════════════ */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  font-size: 0.875rem;
  color: var(--text-primary);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: all var(--transition-smooth);
  z-index: 300;
}

.toast.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.toast.success {
  border-color: var(--success);
}

/* ═══════════════════ RESPONSIVE ═══════════════════ */
@media (max-width: 900px) {
  .converter {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .center-bar {
    flex-direction: row;
    padding: var(--space-md);
    min-width: auto;
  }

  .center-bar__arrow-group {
    flex-direction: row;
  }

  .center-bar__arrow--right svg {
    transform: rotate(90deg);
  }

  .center-bar__arrow--left svg {
    transform: rotate(90deg);
  }

  .info-section {
    grid-template-columns: 1fr;
  }

  .ad-grid {
    grid-template-columns: 1fr;
  }

  .panel__textarea {
    min-height: 200px;
  }
}

@media (max-width: 600px) {
  .header__inner {
    padding: var(--space-sm) var(--space-md);
  }

  .main {
    padding: var(--space-md);
  }

  .lang-selector__label {
    display: none;
  }
}

/* ═══════════════════ ANIMATIONS ═══════════════════ */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.panel {
  animation: fadeIn 0.4s ease-out;
}

.panel--right {
  animation-delay: 0.1s;
}

.info-card {
  animation: fadeIn 0.5s ease-out backwards;
}

.info-card:nth-child(2) { animation-delay: 0.15s; }
.info-card:nth-child(3) { animation-delay: 0.3s; }