/* ==========================================================================
   UXCamp Vietnam - 3D Flying Envelope Feedback Section
   Stylesheet: envelope.css
   Using 100% Typography & Color Tokens from definition.css
   ========================================================================== */

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


/* ==========================================================================
   Envelope Theme Assets & Dark/Light Mode Variables
   ========================================================================== */
:root {
  --envelope-bg-main: url('../asset/icon/evelope-main-light.svg');
  --envelope-bg-back: url('../asset/icon/evelope-back-light.svg');
  --envelope-bg-cover: url('../asset/icon/evelope-cover-light.svg');
  --envelope-liner-bg: linear-gradient(180deg, #BD9C5C 0%, #856E42 100%);
  --envelope-front-fallback-bg: linear-gradient(180deg, #cbae73 0%, #C9AA6D 10%, #B19152 100%);
}

@media (prefers-color-scheme: dark) {
  :root {
    --envelope-bg-main: url('../asset/icon/evelope-main-dark.svg');
    --envelope-bg-back: url('../asset/icon/evelope-back-dark.svg');
    --envelope-bg-cover: url('../asset/icon/evelope-cover-dark.svg');
    --envelope-liner-bg: linear-gradient(180deg, #0E1629 0%, #0F1F43 100%);
    --envelope-front-fallback-bg: linear-gradient(180deg, #243764 0%, #0E1D41 100%);
  }
}

html[data-theme="dark"],
body[data-theme="dark"],
[data-theme="dark"] {
  --envelope-bg-main: url('../asset/icon/evelope-main-dark.svg');
  --envelope-bg-back: url('../asset/icon/evelope-back-dark.svg');
  --envelope-bg-cover: url('../asset/icon/evelope-cover-dark.svg');
  --envelope-liner-bg: linear-gradient(180deg, #0E1629 0%, #0F1F43 100%);
  --envelope-front-fallback-bg: linear-gradient(180deg, #243764 0%, #0E1D41 100%);
}

html[data-theme="light"],
body[data-theme="light"],
[data-theme="light"] {
  --envelope-bg-main: url('../asset/icon/evelope-main-light.svg');
  --envelope-bg-back: url('../asset/icon/evelope-back-light.svg');
  --envelope-bg-cover: url('../asset/icon/evelope-cover-light.svg');
  --envelope-liner-bg: linear-gradient(180deg, #8C2E06 0%, #532613 100%);
  --envelope-front-fallback-bg: linear-gradient(180deg, #EB4F0C 0%, #532613 100%);
}

.spiral-gallery-title {
  position: absolute;
  top: 20vh;
  left: 0;
  width: 100%;
  text-align: center;
  z-index: 10;
  margin: 0;
  pointer-events: none;
  font-style: italic;
}

/* ==========================================================================
   Envelope Feedback Section - 3D Helical Spiral Helix Gallery
   ========================================================================== */
.spiral-gallery-section,
.envelope-gallery-section {
  position: relative;
  width: 100%;
  max-width: 100%;
  height: 100vh;
  min-height: 680px;
  overflow-x: clip;
  overflow-y: visible;
  display: flex;
  align-items: center;
  justify-content: center;
  box-sizing: border-box;
  pointer-events: none;
}

.pin-spacer {
  max-width: 100% !important;
  overflow-x: clip !important;
}

/* 3D Viewport with Deep Perspective */
.spiral-viewport {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  perspective: 1800px;
  perspective-origin: 50% 50%;
  overflow: visible;
  cursor: default;
  user-select: none;
  touch-action: pan-y;
  transform-style: preserve-3d;
  pointer-events: none;
  overflow-y: visible;
}

/* 3D Stage Container */
.spiral-stage {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  transform-style: preserve-3d;
  will-change: transform;
  pointer-events: none;
}

/* Spiral Track Centered Zero-Size Pivot */
.spiral-track {
  position: relative;
  width: 0;
  height: 0;
  transform-style: preserve-3d;
  will-change: transform;
  pointer-events: none;
}

/* Envelope Card: 3D Positioning with GPU Acceleration */
.envelope-card {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 440px;
  aspect-ratio: 900 / 677;
  margin-top: -165px;
  margin-left: -220px;
  cursor: pointer;
  outline: none;
  transform-style: preserve-3d;
  transform-origin: 50% 50%;
  will-change: transform;
  transition: box-shadow 0.25s ease;
  border-radius: 6px;
  pointer-events: auto;
  transition: filter 0.2s ease-in-out;
}

.envelope-card:focus-visible {
  outline: 2px solid var(--main-color, #eb4f0c);
  outline-offset: 4px;
}

.envelope-card h3,
.envelope-card p {
  filter: drop-shadow(0 0.2px 0 rgba(0, 0, 0, 0.4));
}


/* Loading & Empty State */
.spiral-loading-state,
.envelope-loading-state,
.envelope-empty-state {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  text-align: center;
  color: var(--main-colors-foreground-f700);
  padding: 40px;
  white-space: nowrap;
  z-index: 10;
}

/* ==========================================================================
   ENVELOPE 3D DUAL-FACED CARDS (ORBIT & SPIRAL)
   ========================================================================== */

/* Background Image Divs for Envelopes */
.face-bg,
.envelope-card-bg,
.envelope-cover-flap-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  background-size: 100% 100%;
  background-position: center;
  background-repeat: no-repeat;
  display: block;
}

.envelope-face-main-bg,
.envelope-card-front .envelope-card-bg,
.envelope-face-front .face-bg {
  background-image: var(--envelope-bg-main);
}

.envelope-face-back-bg,
.envelope-card-back .envelope-card-bg,
.envelope-face-back .face-bg {
  background-image: var(--envelope-bg-back);
}

.envelope-cover-flap-bg,
.envelope-card-cover-flap .envelope-cover-flap-bg,
.envelope-cover-flap .envelope-cover-flap-bg {
  background-image: var(--envelope-bg-cover);
}

/* Explicit @media rules for dark & light schemes */
@media (prefers-color-scheme: light) {

  .envelope-face-main-bg,
  .envelope-card-front .envelope-card-bg,
  .envelope-face-front .face-bg {
    background-image: url('../asset/icon/evelope-main-light.svg');
  }

  .envelope-face-back-bg,
  .envelope-card-back .envelope-card-bg,
  .envelope-face-back .face-bg {
    background-image: url('../asset/icon/evelope-back-light.svg');
  }

  .envelope-cover-flap-bg,
  .envelope-card-cover-flap .envelope-cover-flap-bg,
  .envelope-cover-flap .envelope-cover-flap-bg {
    background-image: url('../asset/icon/evelope-cover-light.svg');
  }
}

@media (prefers-color-scheme: dark) {

  .envelope-face-main-bg,
  .envelope-card-front .envelope-card-bg,
  .envelope-face-front .face-bg {
    background-image: url('../asset/icon/evelope-main-dark.svg');
  }

  .envelope-face-back-bg,
  .envelope-card-back .envelope-card-bg,
  .envelope-face-back .face-bg {
    background-image: url('../asset/icon/evelope-back-dark.svg');
  }

  .envelope-cover-flap-bg,
  .envelope-card-cover-flap .envelope-cover-flap-bg,
  .envelope-cover-flap .envelope-cover-flap-bg {
    background-image: url('../asset/icon/evelope-cover-dark.svg');
  }
}

/* Mặt trước phong bì trên quỹ đạo */
.envelope-card-front {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  container-type: inline-size;
  transform: rotateY(0deg) translateZ(0.3px);
  transform-style: preserve-3d;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  background: var(--envelope-front-fallback-bg);
  overflow: hidden;
}

/* Lưng trong lót đáy phong bì (Hiển thị khi lật sang 180deg) */
.envelope-card-liner {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  background: var(--envelope-liner-bg);
  transform: rotateY(180deg) translateZ(0px);
  transform-style: preserve-3d;
  pointer-events: none;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

/* Mặt sau phong bì trên quỹ đạo (Hiển thị mượt mà khi xoay lật góc > 90deg) */
.envelope-card-back {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: rotateY(180deg) translateZ(0.2px);
  transform-style: preserve-3d;
  pointer-events: none;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

/* Nắp phong bì mặt sau */
.envelope-card-cover-flap {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: calc(100% * (392 / 677));
  aspect-ratio: 900 / 392;
  transform-origin: 50% 0%;
  transform-style: preserve-3d;
  transform: rotateY(180deg) translateZ(0.3px) rotateX(0deg);
  pointer-events: none;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

/* Page Scroll Lock when modal is open */
html.envelope-modal-open,
body.envelope-modal-open {
  overflow: hidden;
  overscroll-behavior: none;
}

/* ==========================================================================
   3D Interactive Envelope Modal / Overlay
   ========================================================================== */
.envelope-modal {
  position: fixed;
  inset: 0;
  z-index: 9999;
  background: var(--fix-black---black-40);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.5s ease, visibility 0.5s ease;
  padding: 0;
  overscroll-behavior: contain;
}

.envelope-modal.active {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

/* Top-Right Close Button in Modal (Figma 3705:36577) */
.modal-close-btn {
  position: absolute;
  top: 32px;
  right: 32px;
  width: 40px;
  height: 40px;
  border-radius: 999px;
  background: var(--body-background-elevate-2);
  color: var(--main-colors-foreground-f100);
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast, 0.15s ease);
  box-shadow: 0px 1px 1.5px rgba(0, 0, 0, 0.05);
  z-index: 50;
}

.modal-close-btn:hover {
  transform: scale(1.08);
  opacity: 0.85;
}

.modal-close-btn:active {
  transform: scale(0.96);
}

/* Bottom-Center Navigation Bar in Modal (Figma 3705:36577) */
.modal-bottom-nav {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 10px;
  z-index: 50;
}

.modal-nav-btn {
  width: 40px;
  height: 40px;
  border-radius: 999px;
  background: var(--body-background-elevate-2);
  color: var(--main-colors-foreground-f100);
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast, 0.15s ease);
  box-shadow: 0px 1px 1.5px rgba(0, 0, 0, 0.05);
}

.modal-nav-btn:hover {
  transform: scale(1.08);
  opacity: 0.85;
}

.modal-nav-btn:active {
  transform: scale(0.96);
}

.modal-counter-text {
  font-family: var(--font-mono);
  font-size: 17px;
  color: var(--fix-white---white-100, #fff);
  letter-spacing: 0.72px;
  padding: 6px 14px;
  user-select: none;
  white-space: nowrap;
}

/* ==========================================================================
   3D Stage & Envelope Object
   ========================================================================== */
.envelope-modal-stage {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.stage-3d {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  perspective: 2800px;
  perspective-origin: 50% 50%;
}

/* 3D Envelope Container */
.envelope-3d-object {
  position: relative;
  width: min(440px, 86vw);
  aspect-ratio: 900 / 677;
  height: auto;
  transform-style: preserve-3d;
  will-change: transform;
}

/* 3D Envelope Wrapper (animated by GSAP) */
.envelope-wrapper {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  will-change: transform;
}

/* Front Face (Figma 3706:36662) */
.envelope-face-front {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  container-type: inline-size;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: rotateY(0deg) translateZ(0.3px);
  background: var(--envelope-front-fallback-bg);
  transform-style: preserve-3d;
  overflow: hidden;
  box-shadow: 0 20px 50px var(--fix-black---black-60);
}

/* Front Cover: Top-Left Sender Block (Figma 3706:36662) */
.front-sender-block {
  position: absolute;
  top: 7.2cqi;
  left: 7.2cqi;
  max-width: 60%;
  display: flex;
  flex-direction: column;
  gap: 0.5cqi;

}

.front-sender-name {
  font-family: var(--font-serif-family);
  font-size: 5.65cqi;
  font-weight: 500;
  font-style: italic;
  line-height: 1.35;
  color: rgb(255, 243, 214);
  letter-spacing: 0.05cqi;
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.front-sender-title,
.front-cohort-text,
.front-bootcamp-text {
  font-family: var(--font-sans-family);
  font-size: 3.25cqi;
  line-height: 1.4;
  color: rgb(255, 243, 214);
  letter-spacing: 0.04cqi;
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Front Cover: Top-Right Postage Stamp (Figma 3706:36662) */
.front-stamp-area {
  position: absolute;
  top: 6.5cqi;
  right: 7.2cqi;
}

.front-stamp {
  width: 22cqi;
  aspect-ratio: 80 / 61;
  background: url('../asset/icon/stamp.svg') no-repeat center / 100% 100%;
  padding: 1.1cqi 1.2cqi;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
}

.front-stamp img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

/* Front Cover: Bottom-Right Bootcamp & Cohort Block (Figma 3706:36662) */
.front-bootcamp-block {
  position: absolute;
  bottom: 8.5cqi;
  right: 7.2cqi;
  max-width: 90%;
  text-align: right;
  display: flex;
  flex-direction: column;
  gap: 0.2cqi;
}


/* ==========================================================================
   Back Face of Envelope
   ========================================================================== */
.envelope-face-back {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: rotateY(180deg) translateZ(0.2px);
  transform-style: preserve-3d;
  pointer-events: none;
}

/* Interior envelope cavity liner (Behind letter) */
.envelope-interior-liner {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  background: var(--envelope-liner-bg);
  transform: rotateY(180deg) translateZ(0px);
  transform-style: preserve-3d;
  pointer-events: none;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

/* ==========================================================================
   Real Content Letter Inside Envelope Pocket (Compact -> Expanded)
   Matching Figma 3705:36592
   ========================================================================== */
.letter-3d-container,
.letter-3d-card {
  position: absolute;
  top: 14px;
  left: 20px;
  width: 440px;
  box-sizing: border-box;
  max-width: 95vw;
  max-height: 85vh;
  height: 250px;
  background: var(--body-background-elevate-2, #ffffff);
  color: var(--main-colors-foreground-f-500-main, #1a1a1a);
  box-shadow:
    0 4px 24px rgba(0, 0, 0, 0.2),
    0 0 0 1px rgba(0, 0, 0, 0.08);
  padding: 28px;
  border-radius: 12px;
  overflow: hidden;
  transform-style: preserve-3d;
  transform: rotateY(180deg) translate3d(0, 0, 2px);
  will-change: transform, height, width, left, box-shadow, padding;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  gap: 20px;
  touch-action: pan-y;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
}

.letter-3d-container *,
.letter-3d-card * {
  color: var(--main-colors-foreground-f-500-main, #1a1a1a);
}

.letter-content-scroll {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  gap: 20px;
  overflow-y: auto;
  box-sizing: border-box;
}

/* Top Header inside Letter: Avatar + Info on Left, Stamp on Right (Figma 3705:36592) */
.letter-header {
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-shrink: 0;
  width: 100%;
}

.letter-profile,
.letter-header-left {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 12px;
  min-width: 0;
  flex: 1;
}

.letter-avatar {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.letter-profile-info,
.letter-sender-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.letter-name,
.letter-participant-name {
  font-family: var(--font-serif-family, serif);
  font-weight: 500;
  font-style: italic;
  font-size: 20px;
  line-height: 28px;
  color: var(--main-colors-foreground-f-500-main, #1a1a1a) !important;
  letter-spacing: 0.24px;
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.letter-title-company,
.letter-participant-meta {
  font-family: var(--font-sans-family, sans-serif);
  font-weight: 400;
  font-size: 14px;
  line-height: 20px;
  color: var(--main-colors-foreground-f-500-main, #1a1a1a) !important;
  letter-spacing: 0.5px;
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.letter-stamp-box,
.letter-stamp-wrapper .letter-stamp {
  width: 72px;
  height: 54px;
  aspect-ratio: 80 / 61;
  background: url('../asset/icon/stamp.svg') no-repeat center / 100% 100%;
  padding: 4px 5px;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
  filter: drop-shadow(0 2px 6px rgba(0, 0, 0, 0.15));
  flex-shrink: 0;
}

.letter-stamp-box img,
.letter-stamp-wrapper .letter-stamp img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 2px;
  display: block;
}

/* Feedback Body Paragraph (Figma 3705:36592) */
.letter-body {
  color: var(--main-colors-foreground-f-500-main, #1a1a1a) !important;
  white-space: pre-wrap;
  flex-grow: 1;
  margin: 0;
}

/* Horizontal Divider (Figma 3705:36592) */
.letter-divider {
  border: none;
  border-top: 1px solid var(--transparent-foreground-main-color-20, rgba(0, 0, 0, 0.1));
  width: 100%;
  margin: 0;
  flex-shrink: 0;
}

/* Footer: Bootcamp & Cohort Information (Figma 3705:36592) */
.letter-footer {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex-shrink: 0;
  margin-top: auto;
}

.letter-bootcamp,
.letter-cohort,
.letter-bootcamp-info,
.letter-cohort-info {
  font-family: var(--font-sans-family, sans-serif);
  font-size: 13px;
  line-height: 20px;
  letter-spacing: -0.1px;
  color: var(--main-colors-foreground-f800, #636270) !important;
  margin: 0;
}

@media (max-width: 768px) {
  .letter-3d-card {
    padding: 20px 16px;
    gap: 20px;
  }

  .letter-avatar {
    width: 48px;
    height: 48px;
  }

  .letter-participant-name {
    font-size: 17px;
    line-height: 24px;
  }

  .letter-participant-meta {
    font-size: 12px;
    line-height: 18px;
  }

  .letter-stamp-wrapper .letter-stamp {
    width: 52px;
    height: 38px;
  }
}

/* Front Pocket mask (evelope-back.svg) - Covers bottom 2/3 */
.envelope-pocket-overlay {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: translateZ(0.25px);
  pointer-events: none;
}

.envelope-pocket-overlay img {
  width: 100%;
  height: 100%;
  object-fit: fill;
  display: block;
}

/* Envelope Top Flap Cover */
.envelope-cover-flap {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: calc(100% * (392 / 677));
  aspect-ratio: 900 / 392;
  transform-origin: 50% 0%;
  transform-style: preserve-3d;
  transform: rotateY(180deg) translateZ(6px);
  will-change: transform;
}

/* Inner Flap Face (When flipped up 180deg) */
.envelope-cover-flap .flap-inside {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  transform: rotateX(180deg);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Loading Spinner & Animation */

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--transparent-foreground-main-color-20);
  border-top-color: var(--main-color);
  animation: spin 0.8s linear infinite;
  border-radius: 50%;
}

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

/* Custom Scrollbar for letter */
.letter-3d-card::-webkit-scrollbar {
  width: 3px;
}

.letter-3d-card::-webkit-scrollbar-track {
  background: var(--transparent-foreground-main-color-05);
}

.letter-3d-card::-webkit-scrollbar-thumb {
  background: var(--transparent-foreground-main-color-30);
  border-radius: 3px;
}

/* ==========================================================================
   Responsive Adaptations for 3D Helix
   ========================================================================== */
@media (max-width: 1024px) {
  .envelope-card {
    width: 380px;
    margin-top: -142px;
    margin-left: -190px;
  }
}

@media (max-width: 768px) {

  .spiral-gallery-section,
  .envelope-gallery-section {
    height: 100vh;
    min-height: 100vh;
  }

  .spiral-viewport {
    perspective: 1200px;
  }

  .envelope-card {
    width: 310px;
    margin-top: -116px;
    margin-left: -155px;
  }
}

@media (max-width: 480px) {
  .envelope-card {
    width: 270px;
    margin-top: -101px;
    margin-left: -135px;
  }
}