/* =========================================================
   style.css — Giao diện So sánh ảnh Before/After
   Font: Be Vietnam Pro (chữ Việt), JetBrains Mono (số liệu)
   Dark mode: tự động theo hệ thống + nút chuyển thủ công
   ========================================================= */

:root {
  /* Bảng màu sáng — tông CAM / XÁM / TRẮNG */
  --bg: #f7f7f8;       /* trắng ngả xám nhẹ */
  --panel: #ffffff;    /* trắng tinh */
  --panel-2: #efefef;  /* xám rất nhạt */
  --border: #dcdcdf;   /* xám viền */
  --text: #2b2b2e;     /* xám than */
  --text-dim: #77777d; /* xám trung tính */
  --before: #8b8b92;   /* XÁM — Before (bản cũ) */
  --after: #f26a1b;    /* CAM — After (bản mới, màu nhấn chủ đạo) */
  --accent: #2b2b2e;
  --danger: #d63a3a;
  --shadow: 0 12px 32px rgba(43, 43, 46, .10);
  --radius: 14px;
}

html[data-theme="dark"] {
  /* Dark mode: xám than + cam sáng */
  --bg: #17171a;
  --panel: #202024;
  --panel-2: #2a2a2f;
  --border: #3a3a41;
  --text: #ececee;
  --text-dim: #9d9da5;
  --before: #a3a3ab;   /* xám sáng */
  --after: #ff7a2e;    /* cam sáng */
  --accent: #ececee;
  --danger: #ff6060;
  --shadow: 0 12px 32px rgba(0, 0, 0, .45);
}

/* Nếu người dùng chưa chọn thủ công, theo hệ thống */
@media (prefers-color-scheme: dark) {
  html:not([data-theme]) {
    --bg: #17171a; --panel: #202024; --panel-2: #2a2a2f;
    --border: #3a3a41; --text: #ececee; --text-dim: #9d9da5;
    --before: #a3a3ab; --after: #ff7a2e; --accent: #ececee;
    --danger: #ff6060; --shadow: 0 12px 32px rgba(0, 0, 0, .45);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

/* QUAN TRỌNG: đảm bảo thuộc tính hidden luôn thắng mọi display trong file này
   (không có dòng này, .dz-loading { display:grid } sẽ ghi đè [hidden]
   khiến overlay loading hiện thường trực) */
[hidden] { display: none !important; }

html, body { height: 100%; }

body {
  font-family: "Be Vietnam Pro", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  transition: background .25s, color .25s;
}

/* ---------------- Header ---------------- */
.site-header {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 20px clamp(16px, 4vw, 48px);
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 34px; height: 34px; border-radius: 9px; position: relative; overflow: hidden;
  background: linear-gradient(100deg, var(--before) 0 50%, var(--after) 50% 100%);
}
.brand-mark i {
  position: absolute; top: 0; bottom: 0; left: 50%; width: 2px;
  background: var(--panel); transform: translateX(-50%);
}
.brand-name { font-size: 1.05rem; font-weight: 600; letter-spacing: .01em; }
.brand-name em { font-style: normal; font-weight: 800; }
.brand-name em:first-of-type { color: var(--before); }
.brand-name em:last-of-type { color: var(--after); }
.brand-slash { color: var(--text-dim); margin: 0 2px; font-weight: 400; }

.header-actions { display: flex; align-items: center; gap: 14px; }
.hint { font-size: .78rem; color: var(--text-dim); }
.icon-btn {
  width: 36px; height: 36px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--panel); color: var(--text); cursor: pointer;
  display: grid; place-items: center;
}
.icon-btn:hover { background: var(--panel-2); }
html[data-theme="dark"] .ic-sun, html:not([data-theme]) .ic-sun { display: none; }
html[data-theme="dark"] .ic-moon { display: block; }
html[data-theme="light"] .ic-moon { display: none; }
html[data-theme="light"] .ic-sun { display: block; }
@media (prefers-color-scheme: dark) {
  html:not([data-theme]) .ic-sun { display: block; }
  html:not([data-theme]) .ic-moon { display: none; }
}
@media (prefers-color-scheme: light) {
  html:not([data-theme]) .ic-sun { display: none; }
  html:not([data-theme]) .ic-moon { display: block; }
}

/* ---------------- Trang upload ---------------- */
.upload-page {
  max-width: 1060px; margin: 0 auto; padding: 8px clamp(16px, 4vw, 48px) 64px;
}
/* ---------------- Hero: tiêu đề + mô tả căn giữa ---------------- */
.hero {
  text-align: center; max-width: 720px; margin: 18px auto 44px; padding: 0 8px;
}
.hero-title {
  font-size: clamp(1.7rem, 4.2vw, 2.6rem); font-weight: 800;
  letter-spacing: -.02em; line-height: 1.15; color: var(--text);
}
.hero-accent { color: var(--after); }
.hero-desc {
  margin: 16px auto 0; max-width: 60ch;
  color: var(--text-dim); font-size: .95rem; line-height: 1.65;
}
.hero-rule {
  width: 72px; height: 4px; border-radius: 99px; margin: 24px auto 0;
  background: linear-gradient(90deg, var(--before), var(--after));
}

.dropzones {
  display: grid; grid-template-columns: 1fr auto 1fr; gap: 0; align-items: stretch;
}

.dropzone {
  position: relative; border: 1.5px dashed var(--border); border-radius: var(--radius);
  background: var(--panel); min-height: 320px; cursor: pointer; outline: none;
  transition: border-color .2s, box-shadow .2s, transform .15s;
  display: flex; flex-direction: column;
}
.dropzone:focus-visible { box-shadow: 0 0 0 3px color-mix(in srgb, var(--after) 40%, transparent); }
#dzBefore:hover, #dzBefore.dragover { border-color: var(--before); }
#dzAfter:hover, #dzAfter.dragover { border-color: var(--after); }
.dropzone.dragover { transform: scale(1.01); box-shadow: var(--shadow); }
.dropzone.has-image { border-style: solid; cursor: default; }

.dz-tag {
  position: absolute; top: -11px; left: 18px; z-index: 2;
  font-size: .72rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase;
  padding: 3px 12px; border-radius: 99px; color: #fff;
}
.dz-tag-before { background: var(--before); }
.dz-tag-after { background: var(--after); }

.dz-inner { flex: 1; display: grid; place-items: center; padding: 24px; position: relative; }

.dz-empty { text-align: center; color: var(--text-dim); }
.dz-empty svg { margin-bottom: 12px; opacity: .7; }
.dz-empty strong { color: var(--text); font-weight: 600; }
.dz-sub { font-size: .85rem; margin-top: 4px; }
.dz-formats { font-size: .72rem; margin-top: 10px; opacity: .75; }

.dz-preview { width: 100%; text-align: center; }
.dz-preview img {
  max-width: 100%; max-height: 220px; border-radius: 8px;
  box-shadow: var(--shadow); background: repeating-conic-gradient(var(--panel-2) 0 25%, transparent 0 50%) 0 / 16px 16px;
}
.dz-meta {
  display: flex; justify-content: center; gap: 14px; margin-top: 10px;
  font-family: "JetBrains Mono", monospace; font-size: .76rem; color: var(--text-dim);
}
.dz-remove {
  margin-top: 10px; font: inherit; font-size: .8rem; color: var(--text-dim);
  background: none; border: 1px solid var(--border); border-radius: 8px;
  padding: 5px 14px; cursor: pointer;
}
.dz-remove:hover { color: var(--text); background: var(--panel-2); }

/* Overlay "Đang tải lên…" được JS tự tạo với style inline (xem app.js)
   — chỉ cần giữ keyframes cho vòng quay: */
@keyframes spin { to { transform: rotate(360deg); } }

.dz-error {
  color: var(--danger); font-size: .82rem; padding: 0 18px 14px; text-align: center;
}

/* Thanh chia trang trí giữa 2 ô — nhắc lại motif divider của viewer */
.dz-divider {
  width: 56px; display: grid; place-items: center; position: relative;
}
.dz-divider::before {
  content: ""; position: absolute; top: 8%; bottom: 8%; left: 50%; width: 2px;
  background: linear-gradient(to bottom, var(--before), var(--after));
  transform: translateX(-50%); border-radius: 2px; opacity: .7;
}
.dz-divider-knob {
  position: relative; z-index: 1; width: 34px; height: 34px; border-radius: 50%;
  background: var(--panel); border: 1.5px solid var(--border);
  display: grid; place-items: center; font-size: .9rem; color: var(--text-dim);
  box-shadow: var(--shadow);
}

/* ---------------- Nút SO SÁNH ---------------- */
.compare-cta { text-align: center; margin-top: 36px; }
.btn-compare {
  font: inherit; font-weight: 800; letter-spacing: .14em; font-size: 1rem;
  display: inline-flex; align-items: center; gap: 10px;
  padding: 15px 42px; border-radius: 99px; border: none; cursor: pointer;
  color: #fff; background: linear-gradient(100deg, var(--before), var(--after));
  box-shadow: var(--shadow); transition: transform .15s, opacity .2s, filter .2s;
}
.btn-compare:hover:not(:disabled) { transform: translateY(-2px); filter: brightness(1.06); }
.btn-compare:disabled { opacity: .35; cursor: not-allowed; filter: grayscale(.6); }
.cta-hint { margin-top: 12px; font-size: .8rem; color: var(--text-dim); }

/* ---------------- Viewer fullscreen ---------------- */
.viewer {
  position: fixed; inset: 0; z-index: 100; background: #141416;
  color: #ececee; touch-action: none; overscroll-behavior: contain;
}
.viewer[hidden] { display: none; }

.stage { position: absolute; inset: 0; overflow: hidden; cursor: grab; }
.stage.panning { cursor: grabbing; }

.world { position: absolute; top: 0; left: 0; transform-origin: 0 0; will-change: transform; }
.world img {
  position: absolute; top: 0; left: 0; user-select: none; pointer-events: none;
  image-rendering: auto;
}
/* Khi zoom > 300%, chuyển sang pixelated để soi pixel rõ ràng (JS bật class) */
.world.pixelated img { image-rendering: pixelated; }

.after-clip { position: absolute; inset: 0; overflow: hidden; }

/* Thanh trượt so sánh */
.divider {
  position: absolute; top: 0; bottom: 0; width: 44px; margin-left: -22px;
  cursor: ew-resize; z-index: 5; touch-action: none; outline: none;
}
.divider-line {
  position: absolute; top: 0; bottom: 0; left: 50%; width: 2px;
  transform: translateX(-50%);
  background: #fff; box-shadow: 0 0 0 1px rgba(0,0,0,.35), 0 0 14px rgba(0,0,0,.5);
}
.divider-handle {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);
  width: 42px; height: 42px; border-radius: 50%;
  background: #fff; color: #2b2b2e; display: grid; place-items: center;
  box-shadow: 0 4px 16px rgba(0,0,0,.45); transition: transform .12s;
}
.divider:hover .divider-handle,
.divider:focus-visible .divider-handle { transform: translate(-50%, -50%) scale(1.12); }

.label {
  position: absolute; top: 18px; z-index: 4; pointer-events: none;
  font-size: .72rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase;
  padding: 5px 14px; border-radius: 99px; color: #fff;
  box-shadow: 0 2px 10px rgba(0,0,0,.4);
}
.label-before { left: 18px; background: var(--before); }
.label-after { right: 18px; background: var(--after); }

/* Thanh công cụ viewer */
.viewer-toolbar {
  position: absolute; left: 50%; bottom: max(18px, env(safe-area-inset-bottom));
  transform: translateX(-50%); z-index: 6;
  display: flex; gap: 10px; padding: 8px;
  background: rgba(24, 24, 27, .85); backdrop-filter: blur(10px);
  border: 1px solid rgba(255,255,255,.12); border-radius: 16px;
}
.tb-group { display: flex; align-items: center; gap: 4px; }
.tb-group + .tb-group { border-left: 1px solid rgba(255,255,255,.12); padding-left: 10px; }
.tb-btn {
  min-width: 38px; height: 38px; border-radius: 10px; border: none; cursor: pointer;
  background: transparent; color: #e8eef5; font: inherit; font-size: 1.05rem;
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
}
.tb-btn:hover { background: rgba(255,255,255,.12); }
.tb-text { font-size: .82rem; font-weight: 600; padding: 0 13px; }
.tb-primary { background: linear-gradient(100deg, var(--before), var(--after)); }
.tb-primary:hover { filter: brightness(1.1); background: linear-gradient(100deg, var(--before), var(--after)); }
.zoom-readout {
  font-family: "JetBrains Mono", monospace; font-size: .8rem; min-width: 58px;
  text-align: center; color: #d9d9de;
}

.ar-warning {
  position: absolute; top: 64px; left: 50%; transform: translateX(-50%); z-index: 6;
  font-size: .78rem; padding: 7px 16px; border-radius: 99px;
  background: rgba(255, 173, 51, .16); color: #ffc766; border: 1px solid rgba(255,173,51,.4);
  max-width: min(92vw, 560px); text-align: center;
}
.viewer-tip {
  position: absolute; top: 18px; left: 50%; transform: translateX(-50%); z-index: 4;
  font-size: .74rem; color: rgba(236,236,238,.65); pointer-events: none;
  background: rgba(24,24,27,.6); padding: 5px 14px; border-radius: 99px;
  transition: opacity .6s;
}
.viewer-tip.fade { opacity: 0; }

/* ---------------- Toast thông báo ---------------- */
.toast {
  position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%);
  z-index: 200; background: var(--accent); color: var(--bg);
  padding: 11px 22px; border-radius: 12px; font-size: .86rem;
  box-shadow: var(--shadow); max-width: 90vw; text-align: center;
}
.toast.error { background: var(--danger); color: #fff; }

/* ---------------- Responsive ---------------- */
@media (max-width: 760px) {
  .hint { display: none; }
  .dropzones { grid-template-columns: 1fr; }
  .dz-divider { width: auto; height: 48px; }
  .dz-divider::before {
    top: 50%; bottom: auto; left: 8%; right: 8%; width: auto; height: 2px;
    background: linear-gradient(to right, var(--before), var(--after));
    transform: translateY(-50%);
  }
  .dropzone { min-height: 240px; }
  .viewer-toolbar { flex-wrap: wrap; justify-content: center; max-width: 94vw; }
  .viewer-tip { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* ---------------- FAQ (SEO section) ---------------- */
.faq { max-width: 720px; margin: 64px auto 0; }
.faq-title {
  text-align: center; font-size: 1.35rem; font-weight: 800;
  letter-spacing: -.01em; margin-bottom: 22px; color: var(--text);
}
.faq-item {
  background: var(--panel); border: 1px solid var(--border);
  border-radius: 12px; margin-bottom: 10px; overflow: hidden;
}
.faq-item summary {
  cursor: pointer; list-style: none; padding: 15px 18px;
  font-weight: 600; font-size: .93rem; color: var(--text);
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; font-weight: 400; font-size: 1.25rem; line-height: 1;
  color: var(--after); transition: transform .2s; flex-shrink: 0;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item[open] summary { border-bottom: 1px solid var(--border); }
.faq-item p {
  padding: 14px 18px 16px; font-size: .89rem; line-height: 1.65;
  color: var(--text-dim);
}
.faq-item p strong { color: var(--text); }