/* CSS Custom Properties for consistent theming */
:root {
    --color-primary: #0056b3;
    --color-secondary: #c9a46a;
    --color-text-primary: #4a4a4a;
    --color-text-secondary: #6c6c6c;
    --color-text-muted: #999;
    --color-background: #fdfaf2;
    --color-background-gradient-start: #e8eaf0;
    --color-background-gradient-end: #d9dce3;
    --color-shadow: rgba(0, 0, 0, 0.2);
    --color-border: #ccc;

    --font-family-primary: 'Lora', serif;
    --font-family-signature: 'Dancing Script', cursive;

    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;

    --border-radius: 4px;
    --box-shadow: 0 15px 45px var(--color-shadow);
    --transition-duration: 0.2s;

    --page-width: 800px;
    --page-aspect-ratio: 8.5 / 11;
    --page-padding: clamp(2rem, 5vh, 4rem) clamp(2.5rem, 6.5vh, 5rem);
}

/* Custom text selection highlighting */
::selection {
    background-color: rgba(255, 235, 59, 0.7) !important;
    color: #333 !important;
    text-shadow: none !important;
}

::-moz-selection {
    background-color: rgba(255, 235, 59, 0.7) !important;
    color: #333 !important;
    text-shadow: none !important;
}

/* Base styles */
body {
    margin: 0;
    font-family: var(--font-family-primary);
    background: url('background.webp') repeat fixed;
    color: var(--color-text-primary);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    padding: var(--spacing-lg);
    box-sizing: border-box;
    perspective: 1000px;
    position: relative;
}

/* iOS Safari fallback - fixed background using pseudo-element */
@supports (-webkit-touch-callout: none) {
    body {
        background: none;
    }

    body::before {
        content: '';
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: url('background.webp') repeat;
        z-index: -1;
        pointer-events: none;
    }
}

/* Letter container - holds multiple pages */
.letter-container {
    width: 100%;
    max-width: var(--page-width);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
}

/* Individual letter page styling */
.letter-page {
    background-color: var(--color-background);
    background-image: url('paper-texture.webp');
    background-size: cover;
    width: auto;
    max-width: 100%;
    height: 85vh;
    aspect-ratio: var(--page-aspect-ratio);
    min-height: 0;
    flex-shrink: 0;
    box-shadow: var(--box-shadow);
    border-radius: var(--border-radius);
    padding: var(--page-padding);
    box-sizing: border-box;
    margin: 0 auto;
    animation: unfold 1.2s cubic-bezier(0.19, 1, 0.22, 1) 0.5s forwards;
    opacity: 0;
    transform-origin: center center;
    page-break-after: always;
    break-after: page;
}

.letter-content {
    height: 100%;
}

/* Header layout with flexbox for audio player and date */
.header-block {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
}

#audio-player-container {
    flex: 1;
    max-width: 65%;
    margin-right: var(--spacing-md);
}

#audio-player-container audio {
    width: 100%;
    height: 40px;
}

.date-block {
    text-align: right;
    margin-bottom: 0;
}

.date {
    font-style: italic;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    margin: 0;
}

.relative-time {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    font-style: italic;
    margin: var(--spacing-xs) 0 0 0;
}

/* Letter content styling */
.salutation {
    font-size: clamp(1.3rem, 2.5vw, 1.8rem);
    font-weight: 700;
    color: #333;
    margin-bottom: var(--spacing-md);
}

.letter-body p {
    font-size: clamp(0.8rem, 1.5vw, 1.05rem);
    line-height: 1.9;
    text-align: justify;
    margin-bottom: 1.05rem;
}

/* Closing section with signature and links */
.closing-block {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    margin-top: var(--spacing-md);
}

.closing {
    font-size: 1.05rem;
    margin: 0;
}

.signature {
    font-family: var(--font-family-signature);
    font-size: clamp(1.7rem, 4vw, 2.5rem);
    color: var(--color-primary);
    margin: var(--spacing-xm) 0;
}

.extra-links {
    font-size: 0.8rem;
}

.extra-links a {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color var(--transition-duration) ease;
}

.extra-links a:hover,
.extra-links a:focus {
    color: var(--color-primary);
    text-decoration: underline;
    outline: none;
}

.link-separator {
    color: var(--color-border);
    margin: 0 0.2rem;
}

.seal {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    color: var(--color-secondary);
    opacity: 0.9;
}

/* Page unfold animation */
@keyframes unfold {
    0% {
        opacity: 0;
        transform: scale(0.8) rotateX(-30deg);
    }

    100% {
        opacity: 1;
        transform: scale(1) rotateX(0deg);
    }
}

/* Styles for stacked page effect */
.letter-container.multi-page-stack {
    display: block;
    /* Override flex layout */
    position: relative;
    padding-top: var(--spacing-lg);
    /* padding-bottom is now set dynamically via JS to control the final page scroll. */
}

.multi-page-stack .letter-page {
    position: sticky;
    top: 5vh;
    margin-bottom: var(--spacing-sm);
    transform-origin: center;
    transition:
        transform 0.3s ease-out,
        opacity 0.3s ease-out;
}

/* Responsive design for mobile devices */
@media (max-width: 800px) {
    :root {
        --page-padding: 1.5rem;
    }

    body {
        padding: var(--spacing-sm);
    }

    .letter-container {
        width: 100%;
        max-width: 100%;
        align-items: center;
    }

    .letter-page {
        height: auto;
        width: 92vw;
        aspect-ratio: var(--page-aspect-ratio);
        max-width: 92vw;
        max-height: none;
        padding: var(--page-padding);
        margin: 0 auto;
        box-sizing: border-box;
    }

    .multi-page-stack .letter-page {
        top: 2vh;
        margin-bottom: var(--spacing-xs);
    }

    .date,
    .relative-time {
        font-size: 0.8rem;
    }

    .extra-links {
        font-size: 0.7rem;
    }
}