/* ===== Paper Bilingual Reader - Main Styles ===== */

:root {
  /* Colors - Light Mode */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-text: #1f2937;
  --color-text-secondary: #6b7280;
  --color-text-muted: #9ca3af;
  --color-bg: #ffffff;
  --color-bg-secondary: #f9fafb;
  --color-border: #e5e7eb;
  --color-border-light: #f3f4f6;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans TC', sans-serif;
  --font-serif: 'Georgia', 'Times New Roman', 'Noto Serif TC', serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;

  /* Spacing - Width Variants */
  --content-width-narrow: 800px;
  --content-width-medium: 1100px;
  --content-width-wide: 1600px;
  --content-max-width: var(--content-width-medium);
  --reading-max-width: 900px;
}

/* ===== Dark Mode ===== */
[data-theme="dark"] {
  --color-primary: #60a5fa;
  --color-primary-dark: #3b82f6;
  --color-text: #f3f4f6;
  --color-text-secondary: #9ca3af;
  --color-text-muted: #6b7280;
  --color-bg: #111827;
  --color-bg-secondary: #1f2937;
  --color-border: #374151;
  --color-border-light: #1f2937;
}

/* Dark mode specific overrides */
[data-theme="dark"] .top-nav__logo svg rect {
  fill: #60a5fa;
}

[data-theme="dark"] .btn--active,
[data-theme="dark"] .btn--secondary.btn--active {
  background: #1e3a5f;
}

[data-theme="dark"] .highlight-yellow {
  background-color: rgba(254, 240, 138, 0.4);
}

[data-theme="dark"] .highlight-green {
  background-color: rgba(187, 247, 208, 0.3);
}

[data-theme="dark"] .highlight-blue {
  background-color: rgba(191, 219, 254, 0.3);
}

[data-theme="dark"] .highlight-pink {
  background-color: rgba(251, 207, 232, 0.3);
}

/* ===== Reset ===== */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
}

/* ===== Top Navigation ===== */
.top-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 56px;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  padding: 0 24px;
  z-index: 100;
}

.top-nav__logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--color-text);
  font-weight: 600;
  font-size: 18px;
}

.top-nav__logo svg {
  flex-shrink: 0;
}

.top-nav__title {
  font-size: 14px;
  font-weight: 400;
  color: var(--color-text-secondary);
  margin-left: 8px;
  padding-left: 12px;
  border-left: 1px solid var(--color-border);
}

.top-nav__spacer {
  flex: 1;
}

.top-nav__actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* ===== Main Content ===== */
.main-content {
  margin-top: 56px;
  min-height: calc(100vh - 56px);
}

.content-wrapper {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 32px 24px;
}

/* ===== Paper Header ===== */
.paper-header {
  text-align: center;
  max-width: var(--reading-max-width);
  margin: 0 auto 40px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--color-border);
}

.paper-header__title {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 16px;
}

.paper-header__authors {
  font-size: 1.1rem;
  color: var(--color-text);
  margin-bottom: 8px;
}

.paper-header__affiliation {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: 16px;
}

.paper-header__meta {
  display: flex;
  justify-content: center;
  gap: 24px;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.paper-header__meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ===== Table of Contents ===== */
.toc {
  position: fixed;
  right: 24px;
  top: 80px;
  width: 220px;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
  padding: 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 13px;
}

.toc__title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-text-secondary);
  margin-bottom: 12px;
}

.toc__list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc__item {
  margin-bottom: 8px;
}

.toc__link {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color 0.15s;
}

.toc__link:hover {
  color: var(--color-primary);
}

.toc__link--active {
  color: var(--color-primary);
  font-weight: 500;
}

/* ===== Footer ===== */
.footer {
  padding: 24px;
  text-align: center;
  font-size: 14px;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
  margin-top: 60px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  border-radius: 6px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s;
  border: 1px solid transparent;
}

.btn--primary {
  background: var(--color-primary);
  color: white;
}

.btn--primary:hover {
  background: var(--color-primary-dark);
}

.btn--secondary {
  background: var(--color-bg);
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn--secondary:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--active,
.btn--secondary.btn--active {
  background: #dbeafe;
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ===== Responsive ===== */
@media (max-width: 1400px) {
  .toc {
    display: none;
  }
}

@media (max-width: 768px) {
  .top-nav {
    padding: 0 16px;
  }

  .top-nav__title {
    display: none;
  }

  .content-wrapper {
    padding: 24px 16px;
  }

  .paper-header__title {
    font-size: 1.5rem;
  }

  .paper-header__meta {
    flex-direction: column;
    gap: 8px;
  }
}