:root {
    --bg-color: #F8F4F1;
    --card-bg: #FFFFFF;
    --text-color: #7A6960;
    --accent-primary: #D4A3A3;
    --accent-secondary: #EADCD0;
    --shadow: 0 10px 25px rgba(122, 105, 96, 0.1);
    font-size: 16px;
    --app-height: 100vh;
}

body {
    font-family: 'IBM Plex Sans Thai', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
}

h1, h2, h3, h4, h5, h6, button, p {
    font-family: 'IBM Plex Sans Thai', sans-serif;
}

#app {
    width: 100%;
    max-width: 420px;
    margin: 0 auto;
    min-height: var(--app-height);
    position: relative;
    overflow: hidden;
}

#preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 1;
    transition: opacity 0.8s ease-in-out;
}

#preloader.hidden {
    opacity: 0;
    pointer-events: none;
}

.loader-icon {
    font-size: 4rem;
    animation: heartbeat 1.5s ease-in-out infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.2); }
}

#home-screen {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    height: var(--app-height);
}

.home-content h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-primary);
}

.home-content p {
    font-size: 1.2rem;
    margin-top: -1rem;
    margin-bottom: 3rem;
    color: var(--text-color);
}

#start-button {
    background-color: var(--accent-primary);
    color: white;
    font-size: 1.1rem;
    font-weight: 500;
    border: none;
    border-radius: 50px;
    padding: 1rem 2.5rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(212, 163, 163, 0.4);
    transition: all 0.3s ease;
}

#start-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(212, 163, 163, 0.5);
}

section {
    position: absolute;
    width: 100%;
    min-height: var(--app-height);
    top: 0;
    left: 0;
    padding: 1.5rem;
    box-sizing: border-box;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.8s ease-in-out;
    transform: scale(0.98);
}
section.active {
    opacity: 1;
    pointer-events: auto;
    position: relative;
    transform: scale(1);
}

#category-screen h1 {
    font-size: 1.5rem;
    color: var(--accent-primary);
    letter-spacing: 1px;
    text-align: center;
    margin-bottom: 0.5rem; /* Adjusted margin */
}

/* ▼▼▼ ADDED THIS SECTION BACK ▼▼▼ */
#category-screen p {
    font-size: 0.8rem;
    color: var(--text-color);
    text-align: center;
    margin-top: 0;
    margin-bottom: 2rem;
}
/* ▲▲▲ END OF SECTION ▲▲▲ */

#category-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    padding-bottom: 2rem;
}
.card-deck {
    aspect-ratio: 2.5 / 3.5;
    cursor: pointer;
    background-color: #ffffff;
    border: 1px solid var(--accent-secondary);
    border-radius: 18px;
    box-shadow: var(--shadow);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: transform 0.3s;
}
.card-deck:hover {
    transform: translateY(-5px);
}
.deck-icon { font-size: 2.5rem; }
.deck-title { font-size: 0.9rem; font-weight: 500; margin-top: 0.5rem; text-align: center; }
.surprise-deck {
    background: linear-gradient(45deg, var(--accent-primary), #eab6b6);
    color: white;
}

#card-screen {
    display: flex;
    flex-direction: column;
    height: var(--app-height);
    padding: 0;
    position: fixed;
    background-color: var(--dynamic-bg-color, var(--bg-color));
    transition: background-color 0.8s ease-in-out;
}

.card-header {
    padding: 0.75rem 1.5rem;
    text-align: center;
    flex-shrink: 0;
    z-index: 10;
}

#category-title {
    font-weight: 500;
    color: var(--dynamic-text-color, var(--text-color));
    transition: color 0.8s ease-in-out;
}

#bottom-nav {
    padding: 1rem;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    flex-shrink: 0;
    z-index: 10;
}

#new-back-button, #undo-button {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: none;
    background-color: var(--dynamic-button-bg, rgba(0,0,0,0.1));
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color 0.4s ease, transform 0.2s ease;
}

#new-back-button:hover, #undo-button:hover {
    transform: scale(1.1);
}

#new-back-button svg, #undo-button svg {
    stroke: var(--dynamic-text-color, var(--text-color));
    transition: stroke 0.8s ease-in-out;
}

#undo-button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: scale(1);
}

#card-stack {
    flex-grow: 1;
    position: relative;
    perspective: 1000px;
    transform-style: preserve-3d;
    padding: 0.5rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 0;
}

.card {
    background-color: var(--card-bg);
    width: 90%;
    max-width: 360px;
    height: 85%;
    max-height: 500px;
    border-radius: 20px;
    box-shadow: var(--shadow), inset 0 0 0 3px var(--bg-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-around;
    padding: 2rem;
    box-sizing: border-box;
    position: absolute;
    user-select: none;
    will-change: transform;
    transition: transform 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.card-numeral {
    position: absolute;
    bottom: 1.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: #d3c8c1;
    user-select: none;
}

.card.swiping {
    transition: none;
}

.card-icon {
    font-size: 2.5rem;
}

#question-text {
    font-size: 1.5rem;
    font-weight: 500;
    line-height: 1.5;
    text-align: center;
    flex-grow: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}