/* ==========================================================================
   Twenty Four – Dark Theme Stylesheet
   ========================================================================== */

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

:root {
    /* Palette */
    --bg-primary: #0f1117;
    --bg-secondary: #1a1d27;
    --bg-card: #242836;
    --bg-input: #1e2230;
    --bg-hover: #2e3348;

    --accent: #7c6aef;
    --accent-hover: #9585f5;
    --accent-glow: rgba(124, 106, 239, 0.25);

    --success: #34d399;
    --success-bg: rgba(52, 211, 153, 0.1);

    --error: #f87171;
    --error-bg: rgba(248, 113, 113, 0.1);

    --text-primary: #e8eaf0;
    --text-secondary: #9ca3b4;
    --text-muted: #5f6678;

    --border: #2e3348;
    --border-focus: #7c6aef;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px var(--accent-glow);

    --font-main:
        "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
        Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", "SF Mono", Consolas, monospace;

    --transition: 0.2s ease;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-main);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100dvh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Screenreader-only utility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ---------- Layout ---------- */
.container {
    width: 100%;
    max-width: 520px;
    margin: 0 auto;
    padding: 24px 20px 40px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    min-height: 100dvh;
}

/* ---------- Main content area ---------- */
main {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* ---------- Header ---------- */
header {
    text-align: center;
}

header h1 {
    font-size: 2rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    background: linear-gradient(
        135deg,
        var(--accent) 0%,
        #b794f6 50%,
        var(--accent-hover) 100%
    );
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
}

.subtitle {
    margin-top: 6px;
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.subtitle .ops {
    font-weight: 600;
    color: var(--accent-hover);
    letter-spacing: 0.08em;
}

.subtitle strong {
    color: var(--text-primary);
    font-weight: 700;
}

/* ---------- Puzzle Date ---------- */
.puzzle-date {
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

/* ---------- Number Cards (tappable) ---------- */
.number-cards {
    display: flex;
    justify-content: center;
    gap: 14px;
    padding: 4px 0;
}

.number-card {
    width: 72px;
    height: 88px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: 800;
    color: var(--text-primary);
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition:
        transform var(--transition),
        border-color var(--transition),
        box-shadow var(--transition),
        opacity var(--transition);
    user-select: none;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
}

.number-card:hover:not(.used) {
    transform: translateY(-2px);
    border-color: var(--accent);
    box-shadow: var(--shadow-glow);
}

.number-card:active:not(.used) {
    transform: translateY(0) scale(0.95);
}

.number-card.used {
    opacity: 0.3;
    cursor: default;
    border-color: var(--border);
    box-shadow: none;
}

/* Skeleton placeholder while loading */
.number-card.skeleton {
    background: linear-gradient(
        90deg,
        var(--bg-card) 25%,
        var(--bg-hover) 50%,
        var(--bg-card) 75%
    );
    background-size: 200% 100%;
    animation: skeleton-pulse 1.5s ease-in-out infinite;
    border-color: transparent;
    cursor: default;
}

@keyframes skeleton-pulse {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

/* ---------- Solve Form ---------- */
#solve-form {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-group {
    display: flex;
    gap: 10px;
}

.input-group input {
    flex: 1;
    padding: 14px 16px;
    font-size: 1.05rem;
    font-family: var(--font-mono);
    color: var(--text-primary);
    background: var(--bg-input);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    outline: none;
    transition:
        border-color var(--transition),
        box-shadow var(--transition);
}

.input-group input::placeholder {
    color: var(--text-muted);
    font-family: var(--font-main);
    font-size: 0.9rem;
}

.input-group input:focus {
    border-color: var(--border-focus);
    box-shadow: var(--shadow-glow);
}

.input-group button {
    padding: 14px 24px;
    font-size: 1rem;
    font-weight: 700;
    color: #fff;
    background: var(--accent);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition:
        background var(--transition),
        transform var(--transition),
        box-shadow var(--transition),
        opacity var(--transition);
    white-space: nowrap;
}

.input-group button:hover:not(:disabled) {
    background: var(--accent-hover);
    box-shadow: var(--shadow-glow);
    transform: translateY(-1px);
}

.input-group button:active:not(:disabled) {
    transform: translateY(0);
}

.input-group button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* ---------- 4×4 Keypad Grid ---------- */
.keypad-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    width: 100%;
}

.key-btn {
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition:
        background var(--transition),
        border-color var(--transition),
        transform var(--transition);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.key-btn:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
}

.key-btn:active {
    transform: scale(0.93);
}

/* Number keys in the grid */
.key-num {
    font-family: var(--font-mono);
    font-weight: 800;
    font-size: 1.3rem;
    color: var(--accent-hover);
    border-color: rgba(124, 106, 239, 0.3);
}

.key-num.used {
    opacity: 0.3;
    pointer-events: none;
}

/* Clear key */
.key-clear {
    color: var(--error);
    border-color: rgba(248, 113, 113, 0.3);
}

.key-clear:hover {
    border-color: var(--error);
    background: var(--error-bg);
}

/* Backspace key */
.key-back {
    color: var(--text-secondary);
}

/* ---------- Feedback ---------- */
.feedback {
    min-height: 0;
    overflow: hidden;
    text-align: center;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
}

.feedback:empty {
    padding: 0;
    margin: 0;
}

.feedback.success {
    padding: 14px 18px;
    color: var(--success);
    background: var(--success-bg);
    border: 1px solid rgba(52, 211, 153, 0.25);
    animation: feedback-appear 0.3s ease;
}

.feedback.error {
    padding: 14px 18px;
    color: var(--error);
    background: var(--error-bg);
    border: 1px solid rgba(248, 113, 113, 0.25);
    animation: feedback-appear 0.3s ease;
}

@keyframes feedback-appear {
    from {
        opacity: 0;
        transform: translateY(-6px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---------- Solutions Count ---------- */
.solutions-count {
    text-align: center;
    font-size: 0.88rem;
    color: var(--text-muted);
}

.solutions-count strong {
    color: var(--accent-hover);
    font-weight: 700;
}

/* ---------- Player Details ---------- */
.player-details {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.player-details summary {
    padding: 12px 16px;
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    list-style: none;
    transition: color var(--transition);
}

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

.player-details summary::before {
    content: "⚙ ";
    opacity: 0.6;
}

.player-details summary:hover {
    color: var(--text-primary);
}

.player-input-wrap {
    display: flex;
    gap: 10px;
    padding: 0 16px 14px;
}

.player-input-wrap input {
    flex: 1;
    padding: 10px 14px;
    font-size: 0.9rem;
    color: var(--text-primary);
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    outline: none;
    transition: border-color var(--transition);
}

.player-input-wrap input:focus {
    border-color: var(--border-focus);
}

.player-input-wrap input::placeholder {
    color: var(--text-muted);
}

.player-input-wrap button {
    padding: 10px 18px;
    font-size: 0.85rem;
    font-weight: 600;
    color: #fff;
    background: var(--accent);
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: background var(--transition);
}

.player-input-wrap button:hover {
    background: var(--accent-hover);
}

/* ---------- Yesterday Section ---------- */
.yesterday-section {
    border-top: 1px solid var(--border);
    padding-top: 8px;
}

.yesterday-toggle {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 4px;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-secondary);
    background: transparent;
    border: none;
    cursor: pointer;
    transition: color var(--transition);
}

.yesterday-toggle:hover {
    color: var(--text-primary);
}

.yesterday-toggle-icon {
    font-size: 0.7rem;
    transition: transform 0.3s ease;
}

.yesterday-toggle.open .yesterday-toggle-icon {
    transform: rotate(180deg);
}

.yesterday-content {
    display: none;
    flex-direction: column;
    gap: 12px;
    padding-bottom: 8px;
}

.yesterday-toggle.open + .yesterday-content {
    display: flex;
    animation: slide-down 0.3s ease;
}

@keyframes slide-down {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.yesterday-header {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-align: center;
    letter-spacing: 0.02em;
}

.yesterday-numbers {
    display: flex;
    justify-content: center;
    gap: 10px;
}

.yesterday-numbers .mini-card {
    width: 44px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-secondary);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

.yesterday-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.loading-text {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.88rem;
    padding: 12px 0;
}

.no-solutions {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.88rem;
    padding: 16px 0;
    font-style: italic;
}

.solution-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 14px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    gap: 12px;
}

.solution-expr {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--accent-hover);
    word-break: break-all;
}

.solution-player {
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
    flex-shrink: 0;
}

.load-more-btn {
    width: 100%;
    padding: 12px;
    margin-top: 4px;
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--accent-hover);
    background: var(--bg-secondary);
    border: 1px dashed var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition:
        background var(--transition),
        border-color var(--transition),
        color var(--transition);
}

.load-more-btn:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
    color: var(--text-primary);
}

.load-more-btn:active {
    transform: scale(0.98);
}

/* ---------- Footer ---------- */
footer {
    text-align: center;
    padding-top: 8px;
}

footer p {
    font-size: 0.78rem;
    color: var(--text-muted);
    letter-spacing: 0.02em;
}

/* ---------- Animations / Misc ---------- */
@keyframes pop-in {
    0% {
        transform: scale(0.6);
        opacity: 0;
    }
    60% {
        transform: scale(1.08);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

.number-card.loaded {
    animation: pop-in 0.35s ease forwards;
}

.number-card.loaded:nth-child(1) {
    animation-delay: 0.05s;
}
.number-card.loaded:nth-child(2) {
    animation-delay: 0.12s;
}
.number-card.loaded:nth-child(3) {
    animation-delay: 0.19s;
}
.number-card.loaded:nth-child(4) {
    animation-delay: 0.26s;
}

/* Submit button spinner state */
.input-group button.loading {
    position: relative;
    color: transparent;
}

.input-group button.loading::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 18px;
    height: 18px;
    margin: -9px 0 0 -9px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* Confetti burst success animation on cards */
.number-card.celebrate {
    animation: celebrate-bounce 0.5s ease;
}

@keyframes celebrate-bounce {
    0%,
    100% {
        transform: translateY(0);
    }
    30% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-4px);
    }
}

/* ---------- Responsive ---------- */

/* Small phones */
@media (max-width: 380px) {
    .container {
        padding: 16px 14px 32px;
        gap: 18px;
    }

    header h1 {
        font-size: 1.6rem;
    }

    .number-card {
        width: 60px;
        height: 74px;
        font-size: 1.6rem;
        border-radius: var(--radius-md);
    }

    .number-cards {
        gap: 10px;
    }

    .input-group input {
        padding: 12px 14px;
        font-size: 0.95rem;
    }

    .input-group button {
        padding: 12px 16px;
        font-size: 0.9rem;
    }

    .keypad-grid {
        gap: 6px;
    }

    .key-btn {
        height: 44px;
        font-size: 1.05rem;
    }

    .key-num {
        font-size: 1.15rem;
    }
}

/* Tablets and larger */
@media (min-width: 600px) {
    .container {
        padding: 40px 24px 60px;
        gap: 28px;
    }

    header h1 {
        font-size: 2.4rem;
    }

    .number-card {
        width: 84px;
        height: 100px;
        font-size: 2.4rem;
        border-radius: var(--radius-xl);
    }

    .number-cards {
        gap: 18px;
    }

    .input-group input {
        padding: 16px 20px;
        font-size: 1.1rem;
    }

    .input-group button {
        padding: 16px 32px;
        font-size: 1.05rem;
    }

    .keypad-grid {
        gap: 10px;
    }

    .key-btn {
        height: 56px;
        font-size: 1.3rem;
        border-radius: var(--radius-md);
    }

    .key-num {
        font-size: 1.4rem;
    }
}

/* Tall-screen devices – give breathing room */
@media (min-height: 750px) {
    .container {
        justify-content: center;
    }
}

/* Prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}