/* ===========================
   Root Variables
   =========================== */
:root {
  --bg: #0d0d0d;
  --bg-2: #161616;
  --bg-3: #1e1e1e;
  --border: #2a2a2a;
  --text: #e8e8e8;
  --text-muted: #888;
  --accent: #c84b31;
  --accent-hover: #e05a3c;
  --radius: 8px;
  --header-height: 60px;
}

/* ===========================
   Reset / Base
   =========================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

a:hover {
  color: var(--accent-hover);
}

/* ===========================
   Header
   =========================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(13, 13, 13, 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
}

.header-inner {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 20px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.02em;
}

.brand:hover {
  color: var(--accent);
}

.nav-link {
  font-size: 0.9rem;
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: var(--radius);
  transition: background 0.2s, color 0.2s;
}

.nav-link:hover {
  color: var(--text);
  background: var(--bg-3);
}

/* ===========================
   Hero
   =========================== */
.hero {
  text-align: center;
  padding: 60px 20px 40px;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 12px;
}

.tagline {
  font-size: 1.2rem;
  color: var(--text-muted);
}

/* ===========================
   Content sections (cards)
   =========================== */
.content-section {
  max-width: 860px;
  width: 100%;
  margin: 0 auto 28px;
  padding: 28px 32px;
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

@media (max-width: 900px) {
  .content-section {
    margin: 0 12px 20px;
    padding: 20px 18px;
  }
}

.content-section h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: var(--text);
}

.content-section p {
  color: var(--text-muted);
  line-height: 1.75;
}

/* Warning box */
.warning-box {
  margin-top: 16px;
  padding: 12px 16px;
  background: rgba(200, 150, 20, 0.12);
  border: 1px solid rgba(200, 150, 20, 0.35);
  border-radius: var(--radius);
  color: #d4a84b;
  font-size: 0.9rem;
  line-height: 1.6;
}

/* How-to list */
.howto-list {
  padding-left: 20px;
  color: var(--text-muted);
  line-height: 1.85;
}

.howto-list li {
  margin-bottom: 6px;
}

.orp-example {
  color: var(--accent);
  font-weight: 600;
}

/* ===========================
   Tabs
   =========================== */
.tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.tab-btn {
  background: var(--bg-3);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 9px 18px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.92rem;
  font-family: inherit;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.tab-btn:hover {
  background: #252525;
  color: var(--text);
}

.tab-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.tab-panel {
  display: block;
}

.tab-panel.hidden {
  display: none;
}

/* ===========================
   Upload Dropzone
   =========================== */
.dropzone {
  position: relative;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 48px 24px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
  background: var(--bg-3);
}

.dropzone:hover,
.dropzone.drag-over {
  border-color: var(--accent);
  background: rgba(200, 75, 49, 0.06);
}

.dropzone input[type="file"] {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.dropzone-label {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  pointer-events: none;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.dropzone-icon {
  font-size: 2.4rem;
}

/* ===========================
   Paste area
   =========================== */
#paste-area {
  width: 100%;
  min-height: 180px;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  padding: 14px 16px;
  resize: vertical;
  line-height: 1.6;
  transition: border-color 0.2s;
  display: block;
  margin-bottom: 12px;
}

#paste-area:focus {
  outline: none;
  border-color: var(--accent);
}

#paste-area::placeholder {
  color: var(--text-muted);
}

/* ===========================
   Buttons (generic)
   =========================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  font-family: inherit;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

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

.btn-secondary {
  background: var(--bg-3);
  color: var(--text);
}

.btn-secondary:hover {
  background: #252525;
  border-color: #3a3a3a;
}

/* ===========================
   Chapter selector
   =========================== */
.chapter-section {
  margin-top: 20px;
}

.chapter-section label {
  display: block;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.chapter-row {
  display: flex;
  gap: 10px;
  align-items: center;
}

#chapter-select {
  flex: 1;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: inherit;
  font-size: 0.92rem;
  padding: 9px 12px;
  cursor: pointer;
  transition: border-color 0.2s;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%23888' d='M6 8L0 0h12z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

#chapter-select:focus {
  outline: none;
  border-color: var(--accent);
}

/* ===========================
   Save section
   =========================== */
.save-section {
  margin-top: 14px;
}

/* ===========================
   Hidden utility
   =========================== */
.hidden {
  display: none !important;
}

/* ===========================
   Reader section
   =========================== */
.reader-section {
  margin-top: 28px;
  border-top: 1px solid var(--border);
  padding-top: 28px;
}

/* ORP marker line above word display */
.orp-marker-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 0;
}

.orp-marker-line {
  width: 2px;
  height: 14px;
  background: var(--accent);
  border-radius: 1px;
  /* horizontally centered inside the word display box */
  position: relative;
}

/* Word display */
.word-display-container {
  background: #111;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  height: 160px;
  overflow: hidden;
  margin-bottom: 20px;
  position: relative;
}

/* Thin vertical guide line centered in word display */
.word-display-container::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 1px;
  background: rgba(200, 75, 49, 0.18);
  pointer-events: none;
}

.word-display {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 0;
  font-family: 'Courier New', Courier, monospace;
  font-size: 5rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1;
  color: var(--text);
  user-select: none;
  transition: font-size 0.1s ease;
}

#word-before,
#word-after {
  color: var(--text);
}

#word-orp {
  color: var(--accent);
}

/* ===========================
   Progress
   =========================== */
.progress-wrap {
  margin-bottom: 20px;
}

.progress-bar-track {
  width: 100%;
  height: 4px;
  background: var(--bg-3);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 8px;
}

.progress-bar-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  width: 0%;
  transition: width 0.15s linear;
}

.progress-counter {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: right;
}

/* ===========================
   Speed controls
   =========================== */
.speed-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  margin-bottom: 20px;
}

.speed-presets {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.speed-btn {
  background: var(--bg-3);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 7px 16px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.88rem;
  font-family: inherit;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
  white-space: nowrap;
}

.speed-btn:hover {
  background: #252525;
  color: var(--text);
}

.speed-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.custom-wpm {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.custom-wpm label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

#custom-wpm-input {
  width: 90px;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: inherit;
  font-size: 0.9rem;
  padding: 7px 10px;
  transition: border-color 0.2s;
}

#custom-wpm-input:focus {
  outline: none;
  border-color: var(--accent);
}

.wpm-badge {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 14px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
  margin-left: auto;
}

/* ===========================
   Playback controls
   =========================== */
.playback-controls {
  display: flex;
  gap: 14px;
  justify-content: center;
  align-items: center;
}

.playback-btn {
  background: var(--bg-3);
  border: 1px solid var(--border);
  color: var(--text);
  width: 52px;
  height: 52px;
  border-radius: 50%;
  font-size: 1.25rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, border-color 0.2s, transform 0.1s;
}

.playback-btn:hover {
  background: #252525;
  border-color: #3a3a3a;
}

.playback-btn:active {
  transform: scale(0.93);
}

.play-pause-btn {
  width: 64px;
  height: 64px;
  font-size: 1.5rem;
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.play-pause-btn:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

/* ===========================
   Footer
   =========================== */
.site-footer {
  margin-top: auto;
  padding: 28px 20px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

.site-footer a {
  color: var(--text-muted);
}

.site-footer a:hover {
  color: var(--accent);
}

/* ===========================
   Responsive
   =========================== */
@media (max-width: 600px) {
  .hero h1 {
    font-size: 2.2rem;
  }

  .word-display {
    font-size: 3.5rem;
  }

  .word-display-container {
    height: 120px;
  }

  .speed-controls {
    flex-direction: column;
    align-items: flex-start;
  }

  .wpm-badge {
    margin-left: 0;
  }

  .playback-btn {
    width: 44px;
    height: 44px;
    font-size: 1.1rem;
  }

  .play-pause-btn {
    width: 56px;
    height: 56px;
    font-size: 1.35rem;
  }
}