/* ======================================= */
/*  QUSUS — Light Novel / Surat Anniversary */
/*  Smooth scroll-snap, immersive design     */
/* ======================================= */

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

/* --- Tokens --- */
:root {
    --serif: 'Cormorant Garamond', 'Georgia', serif;
    --body: 'Lora', 'Georgia', serif;
    --sans: 'Inter', -apple-system, sans-serif;
    --hand: 'Dancing Script', cursive;

    --white: #f5f0eb;
    --cream: #e8ddd0;
    --gold: #c9a96e;
    --gold-dim: rgba(201, 169, 110, 0.5);
    --pink-soft: #d4a0a0;
    --warm: #e8c4a0;
    --dark: #0a0a12;

    /* Fluid typography */
    --fs-xs: clamp(0.65rem, 0.6rem + 0.25vw, 0.75rem);
    --fs-sm: clamp(0.8rem, 0.72rem + 0.4vw, 0.95rem);
    --fs-base: clamp(0.95rem, 0.85rem + 0.5vw, 1.1rem);
    --fs-lg: clamp(1.1rem, 0.95rem + 0.75vw, 1.4rem);
    --fs-xl: clamp(1.6rem, 1.3rem + 1.5vw, 2.4rem);
    --fs-2xl: clamp(2rem, 1.6rem + 2vw, 3rem);
    --fs-hand: clamp(1.8rem, 1.5rem + 1.5vw, 2.8rem);
    --fs-envelope: clamp(1.3rem, 1.1rem + 1vw, 1.8rem);

    /* Smooth transitions */
    --ease-smooth: cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1);
    --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Base --- */
html {
    overflow-x: hidden;
    /* Smooth scroll-snap for defined slide boundaries */
    scroll-behavior: smooth;
    scroll-snap-type: y mandatory;
}

body {
    font-family: var(--body);
    background: var(--dark);
    color: var(--white);
    overflow-x: hidden;
    -webkit-user-select: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    line-height: 1.8;
}

::-webkit-scrollbar {
    width: 0;
    display: none;
}

body {
    scrollbar-width: none;
    -ms-overflow-style: none;
}

/* ======================================= */
/*           COVER / LOADING                */
/* ======================================= */

#cover-page {
    position: fixed;
    inset: 0;
    z-index: 1000;
    background: var(--dark);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: opacity 1.6s var(--ease-out-expo),
        visibility 1.6s var(--ease-out-expo);
}

#cover-page.fade-out {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.cover-content {
    text-align: center;
    padding: 2rem;
}

.cover-ornament {
    font-family: var(--serif);
    font-size: var(--fs-sm);
    color: var(--gold-dim);
    letter-spacing: 1em;
    margin: 1.5rem 0;
}

.cover-title {
    font-family: var(--serif);
    font-size: var(--fs-2xl);
    font-weight: 300;
    color: var(--white);
    letter-spacing: 0.15em;
    margin-bottom: 0.3rem;
    opacity: 0;
    animation: softReveal 2.5s var(--ease-out-expo) 0.3s forwards;
}

.cover-subtitle {
    font-family: var(--body);
    font-size: var(--fs-sm);
    font-weight: 400;
    font-style: italic;
    color: var(--gold);
    opacity: 0;
    animation: softReveal 2.5s var(--ease-out-expo) 0.8s forwards;
}

.cover-hint {
    font-family: var(--sans);
    font-size: var(--fs-xs);
    color: rgba(245, 240, 235, 0.3);
    letter-spacing: 0.3em;
    text-transform: lowercase;
    margin-top: 3rem;
    opacity: 0;
    animation: breathe 3s ease-in-out 2s infinite;
}

/* ======================================= */
/*           CHAPTERS / SLIDES              */
/* ======================================= */

#story.hidden {
    display: none;
}

.chapter {
    position: relative;
    width: 100%;
    min-height: 100vh;
    min-height: 100dvh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    /* Snap each slide into place */
    scroll-snap-align: start;
    scroll-snap-stop: always;
}

/* --- Background Image Layer --- */
.chapter-bg {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    z-index: 0;
    /* Smooth Ken Burns zoom — starts zoomed, relaxes on view */
    transform: scale(1.12);
    transition: transform 12s var(--ease-out-expo),
        opacity 1.8s var(--ease-smooth);
    opacity: 0.7;
}

.chapter.in-view .chapter-bg {
    transform: scale(1);
    opacity: 1;
}

/* --- Overlays --- */
.chapter-overlay {
    position: absolute;
    inset: 0;
    z-index: 1;
    transition: opacity 1.4s var(--ease-smooth);
}

.overlay-dark-heavy {
    background: linear-gradient(180deg,
            rgba(10, 10, 18, 0.88) 0%,
            rgba(10, 10, 18, 0.7) 40%,
            rgba(10, 10, 18, 0.85) 100%);
}

.overlay-dark-soft {
    background: linear-gradient(180deg,
            rgba(10, 10, 18, 0.75) 0%,
            rgba(10, 10, 18, 0.5) 40%,
            rgba(10, 10, 18, 0.75) 100%);
}

.overlay-grey {
    background: linear-gradient(180deg,
            rgba(30, 30, 35, 0.7) 0%,
            rgba(30, 30, 35, 0.45) 40%,
            rgba(30, 30, 35, 0.7) 100%);
}

.overlay-warm {
    background: linear-gradient(180deg,
            rgba(40, 25, 15, 0.6) 0%,
            rgba(30, 20, 10, 0.35) 40%,
            rgba(20, 10, 5, 0.65) 100%);
}

.overlay-light {
    background: linear-gradient(180deg,
            rgba(255, 255, 255, 0.4) 0%,
            rgba(255, 255, 255, 0.2) 50%,
            rgba(255, 255, 255, 0.5) 100%);
}

.overlay-cream {
    background: linear-gradient(180deg,
            rgba(245, 235, 220, 0.55) 0%,
            rgba(245, 235, 220, 0.35) 50%,
            rgba(245, 235, 220, 0.6) 100%);
}

/* --- Chapter Body --- */
.chapter-body {
    position: relative;
    z-index: 5;
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
    padding: clamp(2rem, 5vw, 4rem) clamp(1.5rem, 4vw, 3rem);
    min-height: 100vh;
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.chapter-body-center {
    align-items: center;
    text-align: center;
}

/* --- Part Labels --- */
.part-label {
    display: block;
    font-family: var(--sans);
    font-size: var(--fs-xs);
    font-weight: 400;
    color: var(--gold-dim);
    letter-spacing: 0.3em;
    text-transform: uppercase;
    margin-bottom: 0.3rem;
}

.part-title {
    display: block;
    font-family: var(--serif);
    font-size: var(--fs-sm);
    font-weight: 400;
    font-style: italic;
    color: var(--gold);
    letter-spacing: 0.08em;
    margin-bottom: 0.5rem;
}

/* --- Chapter Titles --- */
.chapter-title {
    font-family: var(--serif);
    font-size: var(--fs-xl);
    font-weight: 300;
    color: var(--white);
    letter-spacing: 0.08em;
    line-height: 1.3;
    margin-bottom: 0.5rem;
}

.title-dark {
    color: #2a2a3a;
}

.title-warm {
    color: var(--cream);
}

/* --- Divider --- */
.divider {
    width: 60px;
    height: 1px;
    background: var(--gold-dim);
    margin: 1rem 0 1.8rem;
}

.divider-dark {
    background: rgba(40, 40, 60, 0.5);
}

.divider-warm {
    background: rgba(232, 196, 160, 0.5);
}

/* --- Narration --- */
.narration {
    font-family: var(--body);
    font-size: var(--fs-base);
    font-weight: 400;
    line-height: 2;
    color: rgba(245, 240, 235, 0.88);
    margin-bottom: 1.5rem;
    text-indent: 1.5em;
}

.narration-accent {
    font-style: italic;
    color: var(--gold);
    text-indent: 0;
    padding-left: 1.2rem;
    border-left: 2px solid var(--gold-dim);
}

.narration-light {
    color: rgba(230, 225, 215, 0.92);
}

.narration-dark {
    color: rgba(30, 30, 45, 0.85);
    text-indent: 0;
    text-align: center;
}

.narration-warm {
    color: rgba(245, 235, 220, 0.92);
}

.narration-warm-accent {
    font-style: italic;
    color: var(--warm);
    text-indent: 0;
    padding-left: 1.2rem;
    border-left: 2px solid rgba(232, 196, 160, 0.4);
}

/* --- Scroll Cue --- */
.scroll-cue {
    font-family: var(--sans);
    font-size: var(--fs-xs);
    color: rgba(245, 240, 235, 0.25);
    letter-spacing: 0.3em;
    text-align: center;
    margin-top: 3rem;
    animation: breathe 3s ease-in-out infinite;
}

/* ======================================= */
/*       SLIDE 0 — ENVELOPE                 */
/* ======================================= */

.envelope-container {
    position: relative;
    width: clamp(260px, 70vw, 360px);
    margin: 0 auto 2rem;
    padding: 2.5rem 2rem;
    background: linear-gradient(145deg, #f5ead6, #e8dbc5);
    border-radius: 4px;
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.12),
        0 2px 12px rgba(0, 0, 0, 0.06);
}

.envelope-flap {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 50px;
    background: linear-gradient(180deg, #e0d2be, transparent);
    clip-path: polygon(0 0, 50% 100%, 100% 0);
    opacity: 0;
    transition: opacity 1.2s var(--ease-smooth);
}

.envelope-body-wrap {
    text-align: center;
}

.envelope-from {
    font-family: var(--hand);
    font-size: var(--fs-envelope);
    font-weight: 500;
    color: #4a3828;
    line-height: 1.6;
}

.envelope-date {
    font-family: var(--hand);
    font-size: clamp(1rem, 0.9rem + 0.5vw, 1.3rem);
    font-weight: 400;
    color: #6a5a48;
    margin-bottom: 0.8rem;
}

.envelope-heart {
    font-size: clamp(1.5rem, 1.2rem + 1vw, 2rem);
    color: #b85050;
    line-height: 1;
}

/* ======================================= */
/*       FINALE — HANDWRITING               */
/* ======================================= */

.finale-container {
    text-align: center;
    max-width: 500px;
}

.handwriting-line {
    font-family: var(--hand);
    font-size: var(--fs-hand);
    font-weight: 600;
    color: #3a2820;
    line-height: 1.6;
    opacity: 0;
    transform: translateY(15px);
    transition: opacity 1.4s var(--ease-out-expo),
        transform 1.4s var(--ease-out-expo);
}

.handwriting-line.visible {
    opacity: 1;
    transform: translateY(0);
}

#line-name {
    margin-bottom: 0.3rem;
}

#line-fullname {
    margin-bottom: 0.5rem;
}

#line-love {
    font-size: var(--fs-hand);
    color: #8b3a3a;
    margin-bottom: 1.5rem;
}

.finale-divider {
    width: 40px;
    height: 1px;
    background: rgba(100, 60, 40, 0.4);
    margin: 1.5rem auto;
    opacity: 0;
    transition: opacity 1.4s var(--ease-smooth) 0.5s;
}

.finale-divider.visible {
    opacity: 1;
}

.finale-anniversary {
    font-family: var(--serif);
    font-size: var(--fs-lg);
    font-weight: 400;
    font-style: italic;
    color: #5a3a2a;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 1.6s var(--ease-out-expo),
        transform 1.6s var(--ease-out-expo);
    margin-bottom: 0.5rem;
}

.finale-anniversary.visible {
    opacity: 1;
    transform: translateY(0);
}

.finale-date {
    font-family: var(--sans);
    font-size: var(--fs-xs);
    color: rgba(80, 60, 40, 0.5);
    letter-spacing: 0.25em;
    opacity: 0;
    transition: opacity 1.4s var(--ease-smooth);
    margin-bottom: 2rem;
}

.finale-date.visible {
    opacity: 1;
}

.restart-btn {
    display: inline-block;
    padding: 0.7rem 2rem;
    border: 1px solid rgba(80, 60, 40, 0.25);
    background: transparent;
    color: rgba(80, 60, 40, 0.5);
    font-family: var(--sans);
    font-size: var(--fs-xs);
    letter-spacing: 0.2em;
    cursor: pointer;
    border-radius: 2px;
    opacity: 0;
    transition: opacity 1s var(--ease-smooth),
        border-color 0.35s ease,
        color 0.35s ease;
}

.restart-btn.visible {
    opacity: 1;
}

.restart-btn:hover,
.restart-btn:active {
    border-color: rgba(80, 60, 40, 0.6);
    color: rgba(80, 60, 40, 0.8);
}

/* ======================================= */
/*      FADE-IN ANIMATIONS (SMOOTH)         */
/* ======================================= */

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 1.2s var(--ease-out-expo),
        transform 1.2s var(--ease-out-expo);
}

.fade-in.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger children within chapter — longer delays for smoother feel */
.chapter-body .fade-in:nth-child(1) {
    transition-delay: 0.1s;
}

.chapter-body .fade-in:nth-child(2) {
    transition-delay: 0.3s;
}

.chapter-body .fade-in:nth-child(3) {
    transition-delay: 0.5s;
}

.chapter-body .fade-in:nth-child(4) {
    transition-delay: 0.7s;
}

.chapter-body .fade-in:nth-child(5) {
    transition-delay: 0.9s;
}

.chapter-body .fade-in:nth-child(6) {
    transition-delay: 1.1s;
}

.chapter-body .fade-in:nth-child(7) {
    transition-delay: 1.3s;
}

.chapter-body .fade-in:nth-child(8) {
    transition-delay: 1.5s;
}

.chapter-body .fade-in:nth-child(9) {
    transition-delay: 1.7s;
}

.chapter-body .fade-in:nth-child(10) {
    transition-delay: 1.9s;
}

/* ======================================= */
/*           KEYFRAMES                      */
/* ======================================= */

@keyframes softReveal {
    0% {
        opacity: 0;
        transform: translateY(12px);
    }

    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes breathe {

    0%,
    100% {
        opacity: 0;
    }

    50% {
        opacity: 0.5;
    }
}

/* ======================================= */
/*         RESPONSIVE                       */
/* ======================================= */

/* Extra small phones */
@media (max-width: 360px) {
    .chapter-body {
        padding: 1.5rem 1.2rem;
    }

    .narration {
        text-indent: 1em;
    }

    .narration-accent,
    .narration-warm-accent {
        padding-left: 0.8rem;
    }

    .envelope-container {
        padding: 2rem 1.5rem;
    }
}

/* Tablets */
@media (min-width: 768px) {
    .chapter-body {
        max-width: 650px;
        padding: 4rem 3rem;
    }
}

/* Desktop */
@media (min-width: 1024px) {
    .chapter-body {
        max-width: 700px;
        padding: 5rem 3.5rem;
    }
}

/* Large desktop */
@media (min-width: 1440px) {
    .chapter-body {
        max-width: 750px;
    }
}

/* Landscape mobile */
@media (max-height: 500px) and (orientation: landscape) {
    .chapter {
        min-height: auto;
        padding: 2rem 0;
    }

    .chapter-body {
        min-height: auto;
    }

    html {
        scroll-snap-type: none;
    }
}

/* Safe area insets */
@supports (padding: max(0px)) {
    .chapter-body {
        padding-left: max(clamp(1.5rem, 4vw, 3rem), env(safe-area-inset-left));
        padding-right: max(clamp(1.5rem, 4vw, 3rem), env(safe-area-inset-right));
    }

    #cover-page {
        padding-top: env(safe-area-inset-top);
        padding-bottom: env(safe-area-inset-bottom);
    }
}

/* Reduce motion */
@media (prefers-reduced-motion: reduce) {
    html {
        scroll-snap-type: none;
        scroll-behavior: auto;
    }

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

    .chapter-bg {
        transform: none !important;
        transition: none !important;
        opacity: 1 !important;
    }
}

/* Print */
@media print {

    .chapter-bg,
    .chapter-overlay,
    .scroll-cue,
    .restart-btn,
    #cover-page {
        display: none !important;
    }

    .chapter {
        min-height: auto;
        page-break-inside: avoid;
    }

    .narration {
        color: #333 !important;
    }
}