/* =====================================================
   Valentine's Day Card — Stylesheet
   iOS-Compatible Edition
   ===================================================== */

:root {
    --pink-light: #fce4ec;
    --pink: #f48fb1;
    --pink-dark: #e91e63;
    --rose: #ff6b81;
    --white: #ffffff;

    --gradient-bg: linear-gradient(135deg, #fce4ec 0%, #f8bbd0 50%, #f48fb1 100%);
    --gradient-card: linear-gradient(145deg, #ffffff 0%, #fce4ec 100%);
    --gradient-btn: linear-gradient(135deg, #e91e63 0%, #ff6b81 100%);

    --shadow-soft: 0 8px 32px rgba(233, 30, 99, 0.15);
    --shadow-card: 0 20px 60px rgba(233, 30, 99, 0.2);
    --shadow-glow: 0 0 30px rgba(233, 30, 99, 0.3);

    --font-thai: 'Kanit', sans-serif;
    --font-cursive: 'Dancing Script', cursive;
    --font-body: 'Quicksand', sans-serif;

    --transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    font-size: 16px;
    /* ป้องกัน iOS ปรับ font-size อัตโนมัติ */
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

body {
    font-family: var(--font-body);
    background: var(--gradient-bg);
    min-height: 100vh;
    /* iOS Safari: dvh = dynamic viewport height */
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    overflow-x: hidden;
    overflow-y: auto;
    position: relative;
    padding: 2rem 1rem;
    /* safe-area สำหรับ iPhone X+ (notch) */
    padding-bottom: calc(1rem + env(safe-area-inset-bottom, 0px));
    gap: 0.5rem;
    /* iOS Safari: ป้องกัน rubber-band scroll flicker */
    -webkit-overflow-scrolling: touch;
}

/* =====================================================
   Background Hearts
   ===================================================== */
.bg-hearts {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.bg-hearts .heart {
    position: absolute;
    font-size: 1.2rem;
    opacity: 0;
    animation: floatHeart linear infinite;
    color: var(--pink-dark);
}

@keyframes floatHeart {
    0% {
        opacity: 0;
        transform: translateY(100vh) rotate(0deg) scale(0.5);
    }

    10% {
        opacity: 0.7;
        transform: translateY(80vh) rotate(72deg) scale(0.6);
    }

    90% {
        opacity: 0.7;
        transform: translateY(0vh) rotate(648deg) scale(1.1);
    }

    100% {
        opacity: 0;
        transform: translateY(-10vh) rotate(720deg) scale(1.2);
    }
}

/* =====================================================
   Page Header
   ===================================================== */
.page-header {
    text-align: center;
    margin-bottom: 1rem;
    z-index: 10;
    position: relative;
    animation: fadeInDown 1s ease-out;
    flex-shrink: 0;
}

.page-header h1 {
    font-family: var(--font-cursive);
    font-size: 3rem;
    font-weight: 700;
    color: var(--pink-dark);
    text-shadow: 2px 2px 4px rgba(233, 30, 99, 0.2);
    letter-spacing: 2px;
    margin-bottom: 0.3rem;
}

.page-header .subtitle {
    font-family: var(--font-thai);
    font-size: 1.1rem;
    font-weight: 300;
    color: var(--rose);
    letter-spacing: 1px;
}

/* =====================================================
   Card Container & Envelope (3D Flip)
   iOS Safari fix: -webkit-perspective + -webkit-transform-style
   ===================================================== */
.card-container {
    -webkit-perspective: 1500px;
    perspective: 1500px;
    z-index: 10;
    position: relative;
    animation: fadeInUp 1.2s ease-out;
}

.envelope-wrapper {
    width: 380px;
    height: 480px;
    position: relative;
    cursor: pointer;
    transition: var(--transition);
}

.envelope-wrapper:hover {
    transform: scale(1.02);
}

/* Keyboard focus indicator */
.envelope-wrapper:focus-visible {
    outline: 3px solid var(--pink-dark);
    outline-offset: 4px;
    border-radius: 24px;
}

.envelope {
    width: 100%;
    height: 100%;
    position: relative;
    /* iOS Safari prefix */
    -webkit-transform-style: preserve-3d;
    transform-style: preserve-3d;
    -webkit-transition: -webkit-transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.envelope.opened {
    -webkit-transform: rotateY(180deg);
    transform: rotateY(180deg);
}

/* =====================================================
   Envelope Front
   iOS Safari fix: -webkit-backface-visibility + translate3d anti-flicker
   ===================================================== */
.envelope-front {
    position: absolute;
    width: 100%;
    height: 100%;
    /* iOS Safari: ป้องกัน backface แสดง */
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    /* iOS Safari: anti-flicker hack */
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
    visibility: visible;
    border-radius: 20px;
    background: var(--gradient-card);
    box-shadow: var(--shadow-card);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    border: 2px solid rgba(233, 30, 99, 0.1);
    z-index: 2;
}

.envelope-front::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 120px;
    background: linear-gradient(180deg, rgba(244, 143, 177, 0.3) 0%, transparent 100%);
    -webkit-clip-path: polygon(0 0, 50% 60%, 100% 0);
    clip-path: polygon(0 0, 50% 60%, 100% 0);
}

.envelope-front::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-btn);
    border-radius: 0 0 20px 20px;
}

.envelope-heart {
    font-size: 5rem;
    margin-bottom: 1.5rem;
    animation: pulse 2s ease-in-out infinite;
    -webkit-filter: drop-shadow(0 4px 8px rgba(233, 30, 99, 0.3));
    filter: drop-shadow(0 4px 8px rgba(233, 30, 99, 0.3));
    position: relative;
    z-index: 2;
}

.envelope-label {
    font-family: var(--font-cursive);
    font-size: 1.8rem;
    color: var(--pink-dark);
    margin-bottom: 0.5rem;
    position: relative;
    z-index: 2;
}

.envelope-hint {
    font-family: var(--font-thai);
    font-size: 0.9rem;
    font-weight: 300;
    color: var(--pink);
    animation: blink 2s ease-in-out infinite;
    position: relative;
    z-index: 2;
}

/* =====================================================
   Corner Decorations
   ===================================================== */
.corner-decor {
    position: absolute;
    font-size: 1.5rem;
    opacity: 0.6;
    z-index: 3;
}

.corner-decor.top-left {
    top: 15px;
    left: 15px;
}

.corner-decor.top-right {
    top: 15px;
    right: 15px;
}

.corner-decor.bottom-left {
    bottom: 15px;
    left: 15px;
}

.corner-decor.bottom-right {
    bottom: 15px;
    right: 15px;
}

/* =====================================================
   Envelope Back (Card Content)
   iOS Safari fix: -webkit-backface-visibility + rotateY(180deg) + 0.01deg hack
   ===================================================== */
.envelope-back {
    position: absolute;
    width: 100%;
    height: 100%;
    /* iOS Safari: ป้องกัน backface แสดง */
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    /* iOS Safari: 0.01deg hack ป้องกัน render bug */
    -webkit-transform: rotateY(180deg) rotateX(0.01deg);
    transform: rotateY(180deg) rotateX(0.01deg);
    visibility: visible;
    border-radius: 20px;
    background: var(--white);
    box-shadow: var(--shadow-card);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    /* ใช้ clamp() ให้ padding ยืดหยุ่นตาม viewport */
    padding: clamp(1rem, 4vw, 2rem) clamp(0.8rem, 3vw, 1.5rem);
    overflow: hidden;
    border: 2px solid rgba(233, 30, 99, 0.1);
    z-index: 1;
}

.envelope-back::before {
    content: '';
    position: absolute;
    /* แก้จาก inset → top/right/bottom/left สำหรับ iOS < 14.5 */
    top: 12px;
    right: 12px;
    bottom: 12px;
    left: 12px;
    border: 2px dashed rgba(233, 30, 99, 0.15);
    border-radius: 14px;
    pointer-events: none;
}

/* =====================================================
   Card Inner Content
   ป้องกันข้อความทับกัน: ใช้ flex containment + overflow safety
   ===================================================== */
.card-inner {
    text-align: center;
    display: -webkit-flex;
    display: flex;
    -webkit-flex-direction: column;
    flex-direction: column;
    -webkit-align-items: center;
    align-items: center;
    gap: 0.6rem;
    width: 100%;
    height: 100%;
    /* iOS Safari: ให้ scroll ได้ถ้าเนื้อหาล้น */
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    /* ป้องกัน flex item ถูกบีบจนทับกัน */
    justify-content: center;
}

.card-inner .card-emoji-top {
    font-size: 2.2rem;
    animation: bounce 2s ease-in-out infinite;
    -webkit-flex-shrink: 0;
    flex-shrink: 0;
    line-height: 1;
}

.card-inner .card-title {
    font-family: var(--font-cursive);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--pink-dark);
    line-height: 1.3;
    -webkit-flex-shrink: 0;
    flex-shrink: 0;
    word-break: break-word;
    /* ป้องกันข้อความล้น */
    max-width: 100%;
    padding: 0 0.3rem;
}

.card-inner .card-divider {
    display: -webkit-flex;
    display: flex;
    -webkit-align-items: center;
    align-items: center;
    -webkit-justify-content: center;
    justify-content: center;
    gap: 0.5rem;
    color: var(--pink);
    font-size: 1rem;
    width: 80%;
    -webkit-flex-shrink: 0;
    flex-shrink: 0;
}

.card-inner .card-divider::before,
.card-inner .card-divider::after {
    content: '';
    -webkit-flex: 1;
    flex: 1;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--pink), transparent);
}

.card-inner .card-message {
    font-family: var(--font-thai);
    font-size: 0.9rem;
    font-weight: 300;
    color: #555;
    line-height: 1.75;
    max-width: 280px;
    width: 100%;
    -webkit-flex-shrink: 0;
    flex-shrink: 0;
    /* ป้องกัน iOS ปรับ font-size อัตโนมัติ */
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
    /* การตัดคำภาษาไทย */
    word-break: keep-all;
    overflow-wrap: break-word;
    /* ป้องกัน iOS Safari จัดคำผิดพลาด */
    -webkit-hyphens: none;
    hyphens: none;
    padding: 0 0.3rem;
}

.card-inner .card-message strong {
    color: var(--pink-dark);
    font-weight: 500;
}

.card-inner .card-signature {
    font-family: var(--font-cursive);
    font-size: 1.1rem;
    color: var(--rose);
    margin-top: 0.2rem;
    -webkit-flex-shrink: 0;
    flex-shrink: 0;
    line-height: 1.3;
}

.card-inner .card-emoji-bottom {
    font-size: 1.4rem;
    display: -webkit-flex;
    display: flex;
    gap: 0.3rem;
    -webkit-flex-shrink: 0;
    flex-shrink: 0;
    line-height: 1;
}

/* =====================================================
   Card Counter Badge
   ===================================================== */
.card-counter {
    display: -webkit-flex;
    display: flex;
    -webkit-align-items: center;
    align-items: center;
    -webkit-justify-content: center;
    justify-content: center;
    gap: 0.4rem;
    margin-bottom: 1rem;
    padding: 0.4rem 1.2rem;
    background: rgba(255, 255, 255, 0.7);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-radius: 50px;
    border: 1px solid rgba(233, 30, 99, 0.15);
    box-shadow: 0 4px 15px rgba(233, 30, 99, 0.1);
    font-family: var(--font-thai);
    font-size: 0.85rem;
    font-weight: 400;
    color: var(--pink-dark);
}

.card-counter .counter-icon {
    font-size: 1rem;
}

/* =====================================================
   Buttons
   ===================================================== */
.btn-group {
    display: -webkit-flex;
    display: flex;
    -webkit-align-items: center;
    align-items: center;
    -webkit-justify-content: center;
    justify-content: center;
    gap: 0.8rem;
    margin-top: 1.5rem;
    -webkit-flex-wrap: wrap;
    flex-wrap: wrap;
    z-index: 10;
    position: relative;
}

.btn-valentine {
    display: -webkit-inline-flex;
    display: inline-flex;
    -webkit-align-items: center;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.8rem;
    font-family: var(--font-thai);
    font-size: 1rem;
    font-weight: 500;
    color: var(--white);
    background: var(--gradient-btn);
    border: none;
    border-radius: 50px;
    cursor: pointer;
    box-shadow: var(--shadow-soft);
    transition: var(--transition);
    letter-spacing: 0.5px;
    /* iOS Safari: ลบ default tap highlight */
    -webkit-tap-highlight-color: transparent;
    /* iOS Safari: ลบ rounded corners อัตโนมัติ */
    -webkit-appearance: none;
    appearance: none;
}

.btn-valentine:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-glow);
}

.btn-valentine:active {
    transform: translateY(-1px);
}

.btn-valentine:focus-visible {
    outline: 3px solid var(--pink-dark);
    outline-offset: 3px;
}

.btn-valentine .btn-icon {
    font-size: 1.2rem;
    transition: transform 0.3s ease;
}

.btn-valentine:hover .btn-icon {
    transform: scale(1.3);
}

.btn-valentine.btn-shuffle {
    background: linear-gradient(135deg, #ab47bc 0%, #ce93d8 100%);
    box-shadow: 0 8px 32px rgba(171, 71, 188, 0.2);
}

.btn-valentine.btn-shuffle:hover {
    box-shadow: 0 0 30px rgba(171, 71, 188, 0.4);
}

/* =====================================================
   Animations — Shake & Pop
   ===================================================== */
.envelope-wrapper.shake {
    animation: shakeCard 0.4s ease-in-out;
    transform: none;
}

@keyframes shakeCard {

    0%,
    100% {
        transform: translateX(0) rotate(0deg);
    }

    20% {
        transform: translateX(-12px) rotate(-3deg);
    }

    40% {
        transform: translateX(12px) rotate(3deg);
    }

    60% {
        transform: translateX(-8px) rotate(-2deg);
    }

    80% {
        transform: translateX(8px) rotate(2deg);
    }
}

.envelope-wrapper.pop-in {
    animation: popIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes popIn {
    0% {
        transform: scale(0.8);
        opacity: 0.5;
    }

    100% {
        transform: scale(1);
        opacity: 1;
    }
}

/* =====================================================
   Effects — Sparkles & Confetti
   ===================================================== */
.sparkle-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 100;
}

.sparkle {
    position: absolute;
    font-size: 1.5rem;
    animation: sparkleFly 1.5s ease-out forwards;
    pointer-events: none;
}

@keyframes sparkleFly {
    0% {
        opacity: 1;
        -webkit-transform: translate(0, 0) scale(1) rotate(0deg);
        transform: translate(0, 0) scale(1) rotate(0deg);
    }

    100% {
        opacity: 0;
        -webkit-transform: translate(var(--tx), var(--ty)) scale(0) rotate(360deg);
        transform: translate(var(--tx), var(--ty)) scale(0) rotate(360deg);
    }
}

.confetti-heart {
    position: fixed;
    font-size: 1.2rem;
    top: -20px;
    animation: confettiFall linear forwards;
    pointer-events: none;
    z-index: 99;
}

@keyframes confettiFall {
    0% {
        opacity: 1;
        -webkit-transform: translateY(0) rotate(0deg) scale(1);
        transform: translateY(0) rotate(0deg) scale(1);
    }

    100% {
        opacity: 0;
        -webkit-transform: translateY(105vh) rotate(720deg) scale(0.3);
        transform: translateY(105vh) rotate(720deg) scale(0.3);
    }
}

/* =====================================================
   Footer
   ===================================================== */
.page-footer {
    position: relative;
    margin-top: 1.5rem;
    padding-bottom: 1rem;
    /* safe-area สำหรับ iPhone X+ */
    padding-bottom: calc(1rem + env(safe-area-inset-bottom, 0px));
    text-align: center;
    z-index: 10;
    font-family: var(--font-thai);
    font-size: 0.8rem;
    font-weight: 300;
    color: rgba(233, 30, 99, 0.5);
    letter-spacing: 0.5px;
    flex-shrink: 0;
}

.page-footer .footer-hearts {
    font-size: 0.7rem;
    letter-spacing: 3px;
    margin-top: 0.2rem;
}

/* =====================================================
   Keyframes — General
   ===================================================== */
@keyframes fadeInDown {
    from {
        opacity: 0;
        -webkit-transform: translateY(-30px);
        transform: translateY(-30px);
    }

    to {
        opacity: 1;
        -webkit-transform: translateY(0);
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        -webkit-transform: translateY(30px);
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        -webkit-transform: translateY(0);
        transform: translateY(0);
    }
}

@keyframes pulse {

    0%,
    100% {
        -webkit-transform: scale(1);
        transform: scale(1);
    }

    50% {
        -webkit-transform: scale(1.15);
        transform: scale(1.15);
    }
}

@keyframes bounce {

    0%,
    100% {
        -webkit-transform: translateY(0);
        transform: translateY(0);
    }

    50% {
        -webkit-transform: translateY(-10px);
        transform: translateY(-10px);
    }
}

@keyframes blink {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.4;
    }
}

/* =====================================================
   Accessibility — Reduced Motion
   ===================================================== */
@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        -webkit-animation-duration: 0.01ms !important;
        animation-duration: 0.01ms !important;
        -webkit-animation-iteration-count: 1 !important;
        animation-iteration-count: 1 !important;
        -webkit-transition-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }

    .envelope {
        -webkit-transition: none;
        transition: none;
    }

    .envelope.opened {
        -webkit-transform: rotateY(180deg);
        transform: rotateY(180deg);
    }

    .bg-hearts .heart,
    .sparkle,
    .confetti-heart {
        display: none;
    }
}

/* =====================================================
   Responsive — Mobile ≤480px (iPhone 6/7/8/SE2/12 mini)
   ===================================================== */
@media (max-width: 480px) {
    body {
        padding: 1.5rem 0.8rem;
        padding-bottom: calc(0.8rem + env(safe-area-inset-bottom, 0px));
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .page-header .subtitle {
        font-size: 0.9rem;
    }

    .envelope-wrapper {
        width: min(320px, 90vw);
        height: min(420px, 70vh);
        /* iOS Safari fallback: dvh */
        height: min(420px, 70dvh);
    }

    .envelope-heart {
        font-size: 3.5rem;
    }

    .envelope-label {
        font-size: 1.4rem;
    }

    .card-inner {
        gap: 0.5rem;
    }

    .card-inner .card-emoji-top {
        font-size: 1.8rem;
    }

    .card-inner .card-title {
        font-size: 1.3rem;
    }

    .card-inner .card-message {
        font-size: 0.82rem;
        max-width: 240px;
        line-height: 1.65;
    }

    .card-inner .card-signature {
        font-size: 0.95rem;
    }

    .card-inner .card-emoji-bottom {
        font-size: 1.1rem;
    }

    .btn-valentine {
        padding: 0.7rem 1.5rem;
        font-size: 0.9rem;
    }

    .envelope-back {
        padding: clamp(0.8rem, 3vw, 1.8rem) clamp(0.6rem, 2.5vw, 1.2rem);
    }
}

/* =====================================================
   Responsive — Small Mobile ≤375px (iPhone SE 2, iPhone 12 mini)
   ===================================================== */
@media (max-width: 375px) {
    .envelope-wrapper {
        width: min(300px, 90vw);
        height: min(400px, 68vh);
        height: min(400px, 68dvh);
    }

    .card-inner {
        gap: 0.4rem;
    }

    .card-inner .card-emoji-top {
        font-size: 1.6rem;
    }

    .card-inner .card-title {
        font-size: 1.2rem;
    }

    .card-inner .card-message {
        font-size: 0.78rem;
        max-width: 220px;
        line-height: 1.6;
    }

    .card-inner .card-signature {
        font-size: 0.88rem;
    }

    .envelope-back {
        padding: 0.8rem;
    }
}

/* =====================================================
   Responsive — Very Small Mobile ≤320px (iPhone SE 1st gen)
   ===================================================== */
@media (max-width: 320px) {
    .page-header h1 {
        font-size: 1.5rem;
    }

    .page-header .subtitle {
        font-size: 0.8rem;
    }

    .envelope-wrapper {
        width: min(270px, 88vw);
        height: min(360px, 62vh);
        height: min(360px, 62dvh);
    }

    .card-inner {
        gap: 0.3rem;
    }

    .card-inner .card-emoji-top {
        font-size: 1.4rem;
    }

    .card-inner .card-title {
        font-size: 1.1rem;
        line-height: 1.2;
    }

    .card-inner .card-divider {
        font-size: 0.8rem;
        width: 70%;
    }

    .card-inner .card-message {
        font-size: 0.72rem;
        max-width: 200px;
        line-height: 1.55;
    }

    .card-inner .card-signature {
        font-size: 0.8rem;
    }

    .card-inner .card-emoji-bottom {
        font-size: 1rem;
    }

    .envelope-back {
        padding: 0.6rem;
    }

    .envelope-back::before {
        top: 6px;
        right: 6px;
        bottom: 6px;
        left: 6px;
    }

    .btn-valentine {
        padding: 0.6rem 1.2rem;
        font-size: 0.82rem;
    }

    .card-counter {
        font-size: 0.75rem;
        padding: 0.3rem 0.8rem;
    }
}