@font-face {
    font-family: 'HK Super Round Bold';
    font-style: normal;
    font-weight: normal;
    src: local('HK Super Round Bold'), url('HKSuperRound-Bold.woff') format('woff');
    font-display: swap;
}

:root {
    /* Solid, punchy true black contrast for light theme */
    --color-bg: #ffffff;
    --color-surface: #ffffff;
    --color-surface-hover: #f1f5f9;
    --color-text-primary: #000000;
    --color-text-secondary: #1f2937;
    --color-text-muted: #6b7280;
    --color-border: #e2e8f0;
    --color-border-dark: #94a3b8;

    --diffle-green: #4fb061;
    --diffle-yellow: #e8b838;
    --diffle-gray: #878a8c;
    --diffle-dark: #000000;
    --diffle-bg-light: #f8fafc;

    --key-bg: #d3d6da;
    --key-text: #000000;
    --empty-tile-border: #94a3b8;
    --modal-bg: #ffffff;
    --modal-overlay: rgba(0, 0, 0, 0.65);
    --drawer-bg: #ffffff;

    --font-heading: 'Clear Sans', 'Helvetica Neue', Arial, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-body: 'Clear Sans', 'Helvetica Neue', Arial, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    --header-height: 5.4rem;
    --radius-sm: 4px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.18);
}

/* ==========================================================================
   DARK THEME VARIABLES (Crisp Pure White Contrast)
   ========================================================================== */
[data-theme="dark"] {
    --color-bg: #121213;
    --color-surface: #18181b;
    --color-surface-hover: #27272a;
    --color-text-primary: #ffffff;
    --color-text-secondary: #e2e8f0;
    --color-text-muted: #94a3b8;
    --color-border: #27272a;
    --color-border-dark: #3f3f46;

    --diffle-green: #4fb061;
    --diffle-yellow: #e8b838;
    --diffle-gray: #565758;
    --diffle-dark: #ffffff;
    --diffle-bg-light: #1e1e22;

    --key-bg: #818384;
    --key-text: #ffffff;
    --empty-tile-border: #3f3f46;
    --modal-bg: #18181b;
    --modal-overlay: rgba(0, 0, 0, 0.8);
    --drawer-bg: #18181b;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.6);
}

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

html {
    font-size: min(2vw, 10px);
    scroll-behavior: smooth;
    color: var(--color-text-primary);
    font-family: var(--font-body);
    background-color: var(--color-bg);
    margin: 0;
    padding: 0;
    transition: background-color 0.25s ease, color 0.25s ease;
}

body {
    background-color: var(--color-bg);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    font-size: 1.6rem;
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    color: var(--color-text-primary);
}

/* ==========================================================================
   HEADER & NAVIGATION
   ========================================================================== */
.site-header {
    width: 100%;
    height: var(--header-height);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1.8rem;
    transition: background-color 0.25s ease, border-color 0.25s ease;
}

.header-left, .header-right {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    flex: 1;
}

.header-right {
    justify-content: flex-end;
}

.header-center {
    display: flex;
    align-items: center;
    justify-content: center;
}

.brand-title {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 3.2rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--diffle-dark);
    text-decoration: none;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    user-select: none;
    transition: color 0.25s;
}

.brand-logo-img {
    width: 3.4rem;
    height: 3.4rem;
    border-radius: 8px;
    display: inline-block;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(34, 197, 94, 0.25);
}

.drawer-logo-img {
    width: 2.8rem;
    height: 2.8rem;
    border-radius: 7px;
    display: inline-block;
    flex-shrink: 0;
    box-shadow: 0 2px 8px rgba(34, 197, 94, 0.25);
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.7rem;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-primary);
    transition: background-color 0.2s, color 0.2s, transform 0.1s;
}

.icon-btn:hover {
    background-color: var(--color-surface-hover);
    transform: scale(1.06);
}

.icon-btn svg {
    width: 2.4rem;
    height: 2.4rem;
    fill: currentColor;
}

/* Theme Toggle Button */
.theme-toggle-btn {
    position: relative;
}

[data-theme="dark"] .icon-moon {
    display: none;
}

[data-theme="dark"] .icon-sun {
    display: block;
}

:root:not([data-theme="dark"]) .icon-sun {
    display: none;
}

:root:not([data-theme="dark"]) .icon-moon {
    display: block;
}

/* ==========================================================================
   SLIDE-OVER NAVIGATION DRAWER (Desktop & Mobile)
   ========================================================================== */
.nav-drawer-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 998;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.nav-drawer-overlay.active {
    opacity: 1;
    visibility: visible;
}

.nav-drawer {
    position: fixed;
    top: 0;
    left: 0;
    width: 85%;
    max-width: 32rem;
    height: 100vh;
    height: 100dvh;
    background: var(--drawer-bg);
    color: var(--color-text-primary);
    z-index: 999;
    box-shadow: 4px 0 25px rgba(0, 0, 0, 0.25);
    transform: translateX(-100%);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.nav-drawer.open {
    transform: translateX(0);
}

.drawer-header {
    height: var(--header-height);
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--color-border);
}

.drawer-brand {
    font-family: var(--font-heading);
    font-weight: 700;
    font-size: 2.6rem;
    letter-spacing: 0.12em;
    color: var(--diffle-dark);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.drawer-close-btn {
    padding: 0.6rem;
}

.drawer-content {
    flex: 1;
    overflow-y: auto;
    padding: 2rem 1.6rem;
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.drawer-section {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.drawer-section-title {
    font-size: 1.25rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-muted);
    padding: 0 0.6rem;
}

.drawer-nav-list, .drawer-games-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.drawer-nav-item {
    display: flex;
    align-items: center;
    gap: 1.2rem;
    padding: 1.1rem 1.4rem;
    border-radius: var(--radius-md);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--color-text-primary);
    text-decoration: none;
    transition: background-color 0.15s, color 0.15s;
}

.drawer-nav-item:hover, .drawer-nav-item.active {
    background-color: var(--diffle-bg-light);
    color: var(--diffle-green);
}

.drawer-icon {
    font-size: 1.8rem;
    width: 2.2rem;
    text-align: center;
}

/* External Partner Games Cards (Clean Menu Item Style, No external arrow) */
.drawer-game-card {
    display: flex;
    align-items: center;
    gap: 1.2rem;
    padding: 1rem 1.4rem;
    border-radius: var(--radius-md);
    background: var(--diffle-bg-light);
    border: 1px solid var(--color-border);
    text-decoration: none;
    transition: transform 0.15s, border-color 0.15s, background-color 0.15s;
}

.drawer-game-card:hover {
    transform: translateX(4px);
    border-color: var(--diffle-green);
    background-color: var(--color-surface-hover);
}

.game-favicon {
    width: 2.8rem;
    height: 2.8rem;
    border-radius: 6px;
    object-fit: contain;
    background: white;
    padding: 2px;
    border: 1px solid var(--color-border);
    flex-shrink: 0;
}

.game-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.game-info strong {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text-primary);
    line-height: 1.25;
}

.game-info span {
    font-size: 1.2rem;
    color: var(--color-text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-top: 0.1rem;
}

.drawer-footer {
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--color-border);
    font-size: 1.25rem;
    color: var(--color-text-muted);
    text-align: center;
}

.drawer-footer p {
    margin: 0;
}

/* ==========================================================================
   GAME VIEWPORT (1st Screen Fold - 100vh)
   ========================================================================== */
.game-viewport {
    height: calc(100vh - var(--header-height));
    height: calc(100dvh - var(--header-height));
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    max-width: 50rem;
    margin: 0 auto;
    padding: 0.5rem 0.6rem 0.8rem 0.6rem;
    position: relative;
    overflow: hidden;
}

.game-board-container {
    flex: 1;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    overflow-y: auto;
    overflow-x: hidden;
    scroll-behavior: smooth;
    padding: 0.8rem 0;
    -webkit-overflow-scrolling: touch;
}

#board {
    display: flex;
    flex-flow: column nowrap;
    align-items: center;
    width: 100%;
    margin: auto 0;
}

.guess {
    text-align: center;
    white-space: nowrap;
    margin: 0.5rem 0;
    display: flex;
    justify-content: center;
    align-items: center;
}

.empty::before {
    content: "";
    display: inline-block;
    width: 4.2rem;
    height: 4.2rem;
    border-radius: 50%;
    border: 2px dashed var(--empty-tile-border);
    margin: 0 0.2rem;
}

.letter {
    font-family: var(--font-heading);
    display: inline-block;
    position: relative;
    font-size: 2.2rem;
    line-height: 4.2rem;
    width: 4.2rem;
    height: 4.2rem;
    border-radius: 50%;
    border: 1px solid var(--empty-tile-border);
    margin: 0 0.2rem;
    text-align: center;
    vertical-align: middle;
    text-transform: uppercase;
    font-weight: 700;
    user-select: none;
    transition: transform 0.15s ease-out;
}

.letter.absent {
    background-color: var(--diffle-gray);
    color: #ffffff;
    border: none;
}

.letter.present {
    background-color: var(--diffle-yellow);
    color: #ffffff;
    border: none;
}

.letter.head {
    background-color: var(--diffle-green);
    color: #ffffff;
    border: none;
}

.letter.tail {
    background-color: var(--diffle-green);
    color: #ffffff;
    border: none;
}

.letter.tail::before {
    content: "";
    display: block;
    position: absolute;
    background-color: var(--diffle-green);
    z-index: -10;
    top: 0;
    bottom: 0;
    left: -0.2rem;
    right: -0.2rem;
    transform: translate(-50%, 0);
}

.letter.start::after {
    content: "";
    display: block;
    position: absolute;
    background-color: var(--diffle-green);
    z-index: -10;
    top: 0;
    bottom: 0;
    left: -0.2rem;
    right: 50%;
}

.letter.end::after {
    content: "";
    display: block;
    position: absolute;
    background-color: var(--diffle-green);
    z-index: -10;
    top: 0;
    bottom: 0;
    right: -0.2rem;
    left: 50%;
}

/* ==========================================================================
   VIRTUAL KEYBOARD (Crisp Solid Font, Ultra High Contrast)
   ========================================================================== */
.keyboard-container {
    width: 100%;
    max-width: 50rem;
    display: flex;
    flex-direction: column;
    padding-bottom: 0.6rem;
    user-select: none;
}

#keyboard {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    touch-action: manipulation;
    background-color: transparent;
}

#keyboard > div {
    display: flex;
    flex-direction: row;
    justify-content: center;
    width: 100%;
    gap: 0.6rem;
    touch-action: manipulation;
}

#keyboard button {
    font-family: var(--font-body);
    font-weight: 700;
    font-size: 1.35rem;
    height: 5.8rem;
    line-height: 5.8rem;
    flex: 1;
    outline: none;
    border: none;
    cursor: pointer;
    user-select: none;
    background-color: var(--key-bg);
    color: var(--key-text);
    border-radius: var(--radius-sm);
    box-shadow: none;
    display: flex;
    justify-content: center;
    align-items: center;
    text-transform: uppercase;
    transition: background-color 0.12s ease, transform 0.05s ease, color 0.12s ease;
    -webkit-tap-highlight-color: transparent;
    padding: 0;
}

#keyboard button:hover {
    filter: brightness(0.96);
}

#keyboard button:active {
    transform: scale(0.96);
    filter: brightness(0.92);
}

#keyboard button#keyboard_enter {
    flex: 1.5;
    font-size: 1.15rem;
    font-weight: 700;
}

#keyboard button#keyboard_backspace {
    flex: 1.5;
    display: flex;
    justify-content: center;
    align-items: center;
}

#keyboard button#keyboard_backspace svg path {
    fill: var(--key-text);
}

#keyboard button.absent {
    background-color: var(--diffle-gray) !important;
    color: #ffffff !important;
}

#keyboard button.present {
    background-color: var(--diffle-yellow) !important;
    color: #ffffff !important;
}

#keyboard button.correct {
    background-color: var(--diffle-green) !important;
    color: #ffffff !important;
}

#keyboard .spacer {
    flex: 0.5;
}

/* ==========================================================================
   RESULT BOX & SHARE
   ========================================================================== */
#result {
    width: 100%;
    margin: 1.5rem 0;
    padding: 1.8rem;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.result_count {
    font-family: var(--font-heading);
    display: flex;
    flex-flow: row;
    justify-content: center;
    align-items: baseline;
}

.result_count_label {
    line-height: 1.8rem;
    font-size: 1.6rem;
    text-align: left;
    padding-left: 1.5rem;
    display: inline-block;
    color: var(--color-text-secondary);
}

#letters_used, #words_used {
    display: block;
    font-size: 6rem;
    line-height: 6rem;
    color: var(--diffle-dark);
}

.slash {
    height: 7rem;
    width: 0;
    border-left: 2px solid var(--color-border);
    transform: rotate(20deg);
}

.timer {
    font-family: var(--font-heading);
    width: 100%;
    margin-top: 1rem;
}

.timer > h2 {
    text-align: center;
    margin-bottom: 0.5rem;
    font-size: 1.8rem;
    color: var(--color-text-secondary);
}

#timer {
    font-size: 3rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    letter-spacing: 0.08em;
    color: var(--diffle-green);
}

.share {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin-top: 1.5rem;
}

#share_button, #share_image_button {
    background-color: var(--diffle-green);
    color: white;
    font-family: inherit;
    font-weight: 700;
    border-radius: var(--radius-sm);
    cursor: pointer;
    border: none;
    user-select: none;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.6rem;
    text-transform: uppercase;
    font-size: 1.5rem;
    height: 4.8rem;
    transition: opacity 0.2s, transform 0.1s;
}

#share_button {
    flex: 1;
    max-width: 220px;
}

#share_image_button {
    width: 4.8rem;
}

#share_button:hover, #share_image_button:hover {
    opacity: 0.92;
    transform: translateY(-1px);
}

/* ==========================================================================
   MODALS (Help & Stats)
   ========================================================================== */
#help, #stats {
    z-index: 1000;
    position: fixed;
    top: 100vh;
    left: 0;
    right: 0;
    width: 100vw;
    height: 100vh;
    overflow-y: auto;
    background: var(--modal-overlay);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    opacity: 0;
    transition: opacity 0.25s ease-in-out, top 0.01s 0.25s;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 1.5rem;
}

.modal-dialog {
    background: var(--modal-bg);
    color: var(--color-text-primary);
    width: 100%;
    max-width: 52rem;
    max-height: 85vh;
    overflow-y: auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    padding: 2.5rem;
    position: relative;
    text-align: left;
}

input[type=radio]:checked + #help, input[type=radio]:checked + #stats {
    opacity: 1;
    top: 0;
    transition: opacity 0.25s ease-in-out;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 1.2rem;
    margin-bottom: 1.5rem;
}

.modal-header h2 {
    font-family: var(--font-heading);
    font-size: 2.4rem;
    margin: 0;
    color: var(--diffle-dark);
}

.modal-close-btn {
    cursor: pointer;
    background: none;
    border: none;
    padding: 0.6rem;
    color: var(--color-text-secondary);
    display: inline-flex;
    border-radius: 50%;
    transition: background 0.2s, color 0.2s;
}

.modal-close-btn:hover {
    background: var(--color-surface-hover);
    color: var(--color-text-primary);
}

.modal-close-btn svg {
    width: 2.4rem;
    height: 2.4rem;
}

.example {
    background: var(--diffle-bg-light);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1.4rem;
    margin: 1.4rem 0;
}

.example .guess {
    margin: 0.6rem 0;
}

.example p {
    margin: 0.4rem 0;
    font-size: 1.45rem;
    color: var(--color-text-secondary);
}

.stats_container {
    font-family: var(--font-heading);
    display: flex;
    flex-flow: row nowrap;
    justify-content: space-around;
    margin: 2.5rem 0;
}

.stats_number {
    font-size: 3.6rem;
    line-height: 3.6rem;
    text-align: center;
    color: var(--diffle-dark);
}

.stats_label {
    line-height: 1.6rem;
    font-size: 1.4rem;
    text-align: center;
    color: var(--color-text-secondary);
    margin-top: 0.4rem;
}

/* ==========================================================================
   ALERTS / TOAST
   ========================================================================== */
#alert {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    letter-spacing: 0.05rem;
    position: fixed;
    left: 50%;
    transform: translateX(-50%);
    color: white;
    padding: 1.2rem 2.4rem;
    background-color: #000000;
    border: 1px solid #3f3f46;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
    border-radius: var(--radius-md);
    opacity: 0;
    top: -20vh;
    z-index: 1100;
    transition: opacity 0.25s, top 0.25s cubic-bezier(0.18, 0.89, 0.32, 1.28);
    pointer-events: none;
    white-space: nowrap;
}

#alert.visible {
    opacity: 1;
    top: 10vh;
}

/* ==========================================================================
   CONTENT SECTION (Revealed after Scroll)
   ========================================================================== */
.site-content {
    background: var(--color-bg);
    border-top: 1px solid var(--color-border);
    padding: 5rem 1.8rem 3rem 1.8rem;
    font-size: 1.6rem;
    color: var(--color-text-primary);
    transition: background-color 0.25s ease;
}

.content-container {
    max-width: 86rem;
    margin: 0 auto;
}

.hero-content {
    text-align: center;
    margin-bottom: 4rem;
}

.pill-badge {
    display: inline-block;
    background: rgba(79, 176, 97, 0.15);
    color: var(--diffle-green);
    font-size: 1.3rem;
    font-weight: 700;
    padding: 0.4rem 1.2rem;
    border-radius: 999px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 1.2rem;
}

.hero-title {
    font-family: var(--font-heading);
    font-size: 3.2rem;
    line-height: 1.25;
    color: var(--diffle-dark);
    margin: 0 0 1.2rem 0;
    font-weight: 700;
}

.hero-subtitle {
    font-size: 2rem;
    color: var(--color-text-secondary);
    font-weight: 600;
    margin: 0 0 2rem 0;
}

.lead-text {
    font-size: 1.65rem;
    line-height: 1.75;
    color: var(--color-text-secondary);
    max-width: 74rem;
    margin: 0 auto 3rem auto;
    text-align: left;
}

.section-block {
    margin-bottom: 5rem;
}

.section-heading {
    font-family: var(--font-heading);
    font-size: 2.6rem;
    color: var(--diffle-dark);
    margin: 0 0 1.5rem 0;
    position: relative;
    padding-bottom: 0.8rem;
    font-weight: 700;
}

.section-heading::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 5rem;
    height: 3px;
    background: var(--diffle-green);
    border-radius: 2px;
}

.section-p {
    font-size: 1.6rem;
    line-height: 1.75;
    color: var(--color-text-secondary);
    margin-bottom: 1.5rem;
}

/* Feature Cards Grid */
.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.8rem;
    margin: 2.5rem 0;
}

@media (min-width: 640px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.feature-card {
    background: var(--diffle-bg-light);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 2.2rem;
    transition: transform 0.2s, box-shadow 0.2s, background-color 0.25s;
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    font-size: 2.6rem;
    margin-bottom: 1rem;
    display: inline-block;
}

.feature-title {
    font-family: var(--font-heading);
    font-size: 1.85rem;
    color: var(--diffle-dark);
    margin: 0 0 0.8rem 0;
    font-weight: 700;
}

.feature-desc {
    font-size: 1.45rem;
    color: var(--color-text-secondary);
    margin: 0;
    line-height: 1.65;
}

/* Steps Grid */
.steps-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin: 2.5rem 0;
}

.step-card {
    display: flex;
    gap: 1.8rem;
    background: var(--diffle-bg-light);
    border-left: 4px solid var(--diffle-green);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    padding: 1.8rem 2rem;
    border-top: 1px solid var(--color-border);
    border-right: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.step-number {
    font-family: var(--font-heading);
    font-size: 2.4rem;
    color: var(--diffle-green);
    font-weight: 700;
    min-width: 3.5rem;
}

.step-content h3 {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    color: var(--diffle-dark);
    margin: 0 0 0.5rem 0;
    font-weight: 700;
}

.step-content p {
    font-size: 1.5rem;
    color: var(--color-text-secondary);
    margin: 0;
    line-height: 1.65;
}

/* Color Legend Table */
.legend-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.2rem;
    margin: 2rem 0;
}

@media (min-width: 640px) {
    .legend-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 1.4rem;
    padding: 1.4rem 1.6rem;
    background: var(--diffle-bg-light);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

.legend-tile {
    font-family: var(--font-heading);
    font-size: 2rem;
    width: 4rem;
    height: 4rem;
    line-height: 4rem;
    text-align: center;
    border-radius: 50%;
    color: white;
    font-weight: 700;
    flex-shrink: 0;
}

.legend-tile.absent {
    background-color: var(--diffle-gray);
}

.legend-tile.present {
    background-color: var(--diffle-yellow);
}

.legend-tile.head {
    background-color: var(--diffle-green);
}

.legend-tile.tail {
    background-color: var(--diffle-green);
    border-radius: 4px;
}

.legend-text strong {
    display: block;
    font-size: 1.55rem;
    color: var(--diffle-dark);
}

.legend-text span {
    font-size: 1.35rem;
    color: var(--color-text-secondary);
}

/* ==========================================================================
   INTERACTIVE FAQ ACCORDION (Details & Summary)
   ========================================================================== */
.faq-accordion-group {
    display: flex;
    flex-direction: column;
    gap: 1.4rem;
    margin: 2.5rem 0;
}

.faq-accordion {
    background: var(--diffle-bg-light);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.faq-accordion[open] {
    border-color: var(--diffle-green);
    box-shadow: var(--shadow-sm);
}

.faq-summary {
    list-style: none;
    cursor: pointer;
    padding: 1.8rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    user-select: none;
    font-family: var(--font-heading);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--diffle-dark);
    transition: color 0.15s, background-color 0.15s;
}

.faq-summary::-webkit-details-marker {
    display: none;
}

.faq-summary:hover {
    color: var(--diffle-green);
    background-color: var(--color-surface-hover);
}

.faq-chevron {
    width: 2rem;
    height: 2rem;
    fill: currentColor;
    flex-shrink: 0;
    transition: transform 0.25s ease;
}

.faq-accordion[open] .faq-chevron {
    transform: rotate(180deg);
}

.faq-answer-body {
    padding: 0 2rem 2rem 2rem;
    font-size: 1.55rem;
    color: var(--color-text-secondary);
    line-height: 1.75;
    animation: fadeIn 0.2s ease-out;
}

.faq-answer-body p {
    margin: 0;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* CTA Card */
.play-cta-card {
    background: linear-gradient(135deg, #4fb061, #2e7d32);
    color: white;
    border-radius: var(--radius-lg);
    padding: 3.5rem 2rem;
    text-align: center;
    margin: 4rem 0;
    box-shadow: var(--shadow-md);
}

.play-cta-card h2 {
    font-family: var(--font-heading);
    font-size: 2.8rem;
    margin: 0 0 1rem 0;
    color: white;
}

.play-cta-card p {
    font-size: 1.6rem;
    opacity: 0.95;
    margin: 0 0 2rem 0;
    color: white;
}

.cta-play-btn {
    background: white;
    color: #1e702c !important;
    font-family: var(--font-heading);
    font-size: 1.6rem;
    font-weight: 700;
    padding: 1.2rem 3rem;
    border-radius: 999px;
    text-decoration: none;
    display: inline-block;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    transition: transform 0.2s, box-shadow 0.2s;
}

.cta-play-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.25);
}

/* ==========================================================================
   FOOTER (Contains Privacy Policy & Disclaimer)
   ========================================================================== */
.site-footer {
    background: #090d16;
    color: #94a3b8;
    padding: 4.5rem 1.8rem 2.5rem 1.8rem;
    font-size: 1.45rem;
    line-height: 1.7;
    border-top: 1px solid var(--color-border);
}

.footer-container {
    max-width: 86rem;
    margin: 0 auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 3rem;
    margin-bottom: 3.5rem;
}

@media (min-width: 640px) {
    .footer-grid {
        grid-template-columns: 2fr 1fr 1fr;
    }
}

.footer-brand h3 {
    font-family: var(--font-heading);
    font-size: 2.2rem;
    color: white;
    margin: 0 0 1rem 0;
    letter-spacing: 0.08em;
}

.footer-brand p {
    margin: 0;
    color: #94a3b8;
    max-width: 35rem;
}

.footer-col h4 {
    font-family: var(--font-heading);
    font-size: 1.6rem;
    color: white;
    margin: 0 0 1.2rem 0;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--diffle-green);
}

.footer-bottom {
    border-top: 1px solid #1e293b;
    padding-top: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    text-align: center;
}

@media (min-width: 640px) {
    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
    }
}

.footer-bottom p {
    margin: 0;
    font-size: 1.35rem;
}

/* ==========================================================================
   PAGE TEMPLATE (About Us, Contact, Privacy, Disclaimer)
   ========================================================================== */
.page-hero {
    background: var(--diffle-bg-light);
    border-bottom: 1px solid var(--color-border);
    padding: 4.5rem 1.8rem;
    text-align: center;
}

.page-title {
    font-family: var(--font-heading);
    font-size: 3.6rem;
    color: var(--diffle-dark);
    margin: 0 0 1rem 0;
    font-weight: 700;
}

.page-subtitle {
    font-size: 1.7rem;
    color: var(--color-text-secondary);
    max-width: 60rem;
    margin: 0 auto;
}

.page-article {
    max-width: 80rem;
    margin: 4rem auto 6rem auto;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    padding: 3.5rem;
    box-shadow: var(--shadow-sm);
}

.page-article h1, .page-article h2, .page-article h3 {
    font-family: var(--font-heading);
    color: var(--diffle-dark);
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.page-article p {
    font-size: 1.6rem;
    line-height: 1.8;
    color: var(--color-text-secondary);
    margin-bottom: 1.6rem;
}

.page-article ul, .page-article ol {
    margin: 1.5rem 0 2rem 2rem;
    padding: 0;
    color: var(--color-text-secondary);
    font-size: 1.55rem;
    line-height: 1.8;
}

.page-article li {
    margin-bottom: 0.8rem;
}

.page-article a {
    color: var(--diffle-green);
    text-decoration: underline;
}

.contact-card-box {
    background: var(--diffle-bg-light);
    border-left: 4px solid var(--diffle-green);
    border-radius: var(--radius-md);
    padding: 2rem;
    margin: 2.5rem 0;
    border-top: 1px solid var(--color-border);
    border-right: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.contact-card-box h3 {
    margin: 0 0 0.8rem 0;
    font-family: var(--font-heading);
    color: var(--diffle-dark);
}

.contact-email-link {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    font-size: 1.7rem;
    font-weight: 700;
    color: var(--diffle-green) !important;
    text-decoration: none !important;
}

/* ==========================================================================
   RESPONSIVE DESIGN (Mobile & Small screens)
   ========================================================================== */
@media (max-width: 600px) {
    :root {
        --header-height: 5.4rem;
    }
    .brand-title {
        font-size: 2.8rem;
    }
    .site-header {
        padding: 0 1.2rem;
    }
    .page-article {
        padding: 2rem 1.6rem;
        margin: 2rem 1rem 4rem 1rem;
    }
    .letter {
        width: 3.9rem;
        height: 3.9rem;
        font-size: 2rem;
        line-height: 3.9rem;
        margin: 0 0.15rem;
    }
    .empty::before {
        width: 3.9rem;
        height: 3.9rem;
        margin: 0 0.15rem;
    }
    #keyboard {
        gap: 0.6rem;
    }
    #keyboard > div {
        gap: 0.4rem;
    }
    #keyboard button {
        height: 5.4rem;
        line-height: 5.4rem;
        font-size: calc(1.25rem + 1px);
        font-weight: 700;
    }
    #keyboard button#keyboard_enter {
        font-size: calc(1.05rem + 1px);
        font-weight: 700;
    }
    .faq-summary {
        font-size: 1.6rem;
        padding: 1.5rem 1.6rem;
    }
    .faq-answer-body {
        padding: 0 1.6rem 1.6rem 1.6rem;
        font-size: 1.45rem;
    }
}