/* ---- RESET ---- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* ---- ROOT TOKENS ---- */
:root {
    --black: #0a0a0a;
    --white: #f5f5f0;
    --grey-light: #e8e8e3;
    --grey-mid: #999990;
    --grey-dark: #333330;
    --accent: #c8b89a;
    --font-jp: 'Noto Sans JP', sans-serif;
    --font-en: 'Inter', sans-serif;
    --nav-height: 72px;
}

/* ---- PAGE ---- */
html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--black);
    color: var(--white);
    font-family: var(--font-en);
    min-height: 100vh;
    overflow-x: hidden;
}

/* ---- HERO ---- */
.hero {
    position: relative;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: var(--black);
    overflow: hidden;
}

/* Subtle Japanese texture lines in background */
.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        repeating-linear-gradient(0deg,
            transparent,
            transparent 60px,
            rgba(255, 255, 255, 0.018) 60px,
            rgba(255, 255, 255, 0.018) 61px);
    pointer-events: none;
}

.hero-kanji {
    font-family: var(--font-jp);
    font-size: clamp(120px, 25vw, 260px);
    font-weight: 900;
    color: var(--white);
    letter-spacing: -0.02em;
    line-height: 1;
    transition: all 0.6s cubic-bezier(0.16, 1, 0.3, 1);
    user-select: none;
    position: relative;
    z-index: 1;
}

/* Faint red seal stamp feel behind kanji */
.hero-kanji::after {
    content: '🔴';
    position: absolute;
    font-size: 0.18em;
    bottom: 0.1em;
    right: -0.3em;
    opacity: 0.7;
    filter: saturate(1.5);
}

.hero-sub {
    font-family: var(--font-en);
    font-size: clamp(10px, 2vw, 13px);
    font-weight: 500;
    letter-spacing: 0.35em;
    color: var(--grey-mid);
    margin-top: 24px;
    text-transform: uppercase;
    position: relative;
    z-index: 1;
}

.hero-hint {
    position: absolute;
    bottom: 48px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    color: var(--grey-mid);
    font-size: 10px;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    animation: fadeUpDown 2s ease-in-out infinite;
}

.scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--grey-mid), transparent);
}

@keyframes fadeUpDown {

    0%,
    100% {
        opacity: 0.4;
        transform: translateX(-50%) translateY(0);
    }

    50% {
        opacity: 1;
        transform: translateX(-50%) translateY(6px);
    }
}

/* ---- STICKY HEADER ---- */
.sticky-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 56px;
    background-color: rgba(10, 10, 10, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    z-index: 100;
    transition: opacity 0.4s ease, transform 0.4s ease;
}

.sticky-header.hidden {
    opacity: 0;
    pointer-events: none;
    transform: translateY(-100%);
}

.header-kanji {
    font-family: var(--font-jp);
    font-size: 22px;
    font-weight: 700;
    color: var(--white);
}

.header-title {
    font-family: var(--font-en);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.3em;
    color: var(--grey-mid);
    text-transform: uppercase;
}

/* ---- MAIN APP ---- */
.main-app {
    min-height: 100vh;
    background-color: var(--white);
    color: var(--black);
    padding-bottom: calc(var(--nav-height) + 24px);
    padding-top: 56px;
}

.app-inner {
    max-width: 480px;
    margin: 0 auto;
    padding: 40px 24px 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

/* ---- DAY LABEL ---- */
.day-label {
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: var(--grey-mid);
    margin-bottom: 28px;
}

/* ---- LEVEL TOGGLE ---- */
#level-toggle {
    display: flex;
    gap: 8px;
    justify-content: center;
    margin-bottom: 32px;
    background-color: var(--grey-light);
    border-radius: 100px;
    padding: 4px;
}

#level-toggle button {
    padding: 8px 22px;
    border-radius: 100px;
    border: none;
    background-color: transparent;
    color: var(--grey-mid);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.08em;
    cursor: pointer;
    transition: all 0.25s ease;
    font-family: var(--font-en);
    text-transform: uppercase;
}

#level-toggle button:hover {
    color: var(--black);
}

#level-toggle button.active {
    background-color: var(--black);
    color: var(--white);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

/* ---- PROGRESS RING ---- */
.ring-wrap {
    margin-bottom: 40px;
    filter: drop-shadow(0 4px 16px rgba(0, 0, 0, 0.10));
}

/* ---- CHALLENGE BOX ---- */
.challenge-box {
    width: 100%;
    background-color: var(--black);
    border-radius: 24px;
    padding: 36px 32px;
    margin-bottom: 28px;
    position: relative;
    overflow: hidden;
}

/* Subtle texture on challenge box */
.challenge-box::before {
    content: '改';
    position: absolute;
    font-family: var(--font-jp);
    font-size: 140px;
    font-weight: 900;
    color: rgba(255, 255, 255, 0.03);
    bottom: -20px;
    right: -10px;
    line-height: 1;
    pointer-events: none;
    user-select: none;
}

.challenge-label {
    font-size: 9px;
    font-weight: 600;
    letter-spacing: 0.3em;
    color: var(--accent);
    text-transform: uppercase;
    margin-bottom: 16px;
}

#challenge {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--white);
    line-height: 1.55;
    font-family: var(--font-en);
    letter-spacing: -0.01em;
}

/* ---- FOOTER ---- */
.footer {
    font-size: 12px;
    color: var(--grey-mid);
    letter-spacing: 0.05em;
}

/* ---- LEGEND ---- */
.legend-message {
    font-size: 1rem;
    font-weight: 600;
    color: var(--white);
    line-height: 1.6;
}

.card.legend {
    padding: 24px;
}

/* ---- BOTTOM NAV ---- */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background-color: rgba(245, 245, 240, 0.95);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-top: 1px solid rgba(0, 0, 0, 0.07);
    display: flex;
    justify-content: space-around;
    align-items: center;
    z-index: 100;
    padding-bottom: env(safe-area-inset-bottom);
}

.nav-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px 20px;
    border-radius: 12px;
    transition: all 0.2s ease;
    color: var(--grey-mid);
    font-family: var(--font-en);
    text-decoration: none;
}

.nav-btn span {
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.nav-btn.active {
    color: var(--black);
}

.nav-btn.coming-soon {
    opacity: 0.4;
}

.nav-btn:hover:not(.coming-soon) {
    background-color: rgba(0, 0, 0, 0.05);
}

/* ---- TOAST ---- */
.toast {
    position: fixed;
    bottom: calc(var(--nav-height) + 16px);
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background-color: var(--black);
    color: var(--white);
    font-size: 13px;
    font-weight: 500;
    font-family: var(--font-en);
    padding: 10px 20px;
    border-radius: 100px;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    white-space: nowrap;
    z-index: 200;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ---- PERSONAL MARK ---- */
.mark {
    position: fixed;
    bottom: calc(var(--nav-height) + 8px);
    right: 16px;
    font-size: 9px;
    color: rgba(0, 0, 0, 0.2);
    font-family: var(--font-en);
    letter-spacing: 0.5px;
    z-index: 2;
    pointer-events: none;
}

/* ---- SCROLL ANIMATION STATE ---- */
.hero-kanji.shrunk {
    font-size: 28px;
    position: fixed;
    top: 14px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 101;
    color: var(--white);
}

.hero-kanji.shrunk::after {
    display: none;
}

/* ---- RESPONSIVE ---- */
@media (max-width: 400px) {
    .app-inner {
        padding: 32px 16px 16px;
    }

    #challenge {
        font-size: 1.25rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    .hero-hint {
        animation: none;
    }

    .hero-kanji {
        transition: none;
    }
}

/* ==========================================================
   DAILY FACT BOX (index.html)
   ========================================================== */

.fact-box {
    width: 100%;
    background-color: transparent;
    border: 1px solid rgba(0, 0, 0, 0.1);
    border-radius: 16px;
    padding: 20px 24px;
    margin-bottom: 24px;
    text-align: left;
}

.fact-label {
    font-size: 9px;
    font-weight: 600;
    letter-spacing: 0.25em;
    color: var(--accent);
    text-transform: uppercase;
    margin-bottom: 8px;
}

#dailyFact {
    font-size: 0.9rem;
    color: var(--grey-dark);
    line-height: 1.6;
    font-family: var(--font-en);
}

/* ==========================================================
   EXERCISE GALLERY (gallery.html)
   ========================================================== */

.gallery-topbar {
    background-color: var(--black);
    padding: 28px 24px 24px;
    text-align: center;
}

.gallery-topbar .header-kanji {
    font-size: 32px;
    display: block;
}

.gallery-topbar .header-title {
    display: block;
    margin-top: 6px;
    font-size: 11px;
}

.gallery-intro {
    color: var(--grey-mid);
    font-size: 12px;
    letter-spacing: 0.03em;
    margin-top: 10px;
}

.gallery-main {
    background-color: var(--white);
    min-height: 100vh;
    padding-bottom: calc(var(--nav-height) + 24px);
}

.gallery-inner {
    max-width: 640px;
    margin: 0 auto;
    padding: 24px 20px 12px;
}

/* Filter chip rows */
.filter-group {
    margin-bottom: 16px;
}

.filter-group-label {
    font-size: 9px;
    font-weight: 700;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--grey-mid);
    margin-bottom: 8px;
}

.chip-row {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 4px;
    scrollbar-width: none;
}

.chip-row::-webkit-scrollbar {
    display: none;
}

.chip {
    flex: 0 0 auto;
    padding: 7px 16px;
    border-radius: 100px;
    border: 1px solid rgba(0, 0, 0, 0.12);
    background-color: transparent;
    color: var(--grey-dark);
    font-size: 12px;
    font-weight: 600;
    font-family: var(--font-en);
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.chip:hover {
    border-color: var(--black);
}

.chip.active {
    background-color: var(--black);
    border-color: var(--black);
    color: var(--white);
}

/* Result count */
.result-count {
    font-size: 11px;
    color: var(--grey-mid);
    margin: 18px 0 12px;
    letter-spacing: 0.03em;
}

/* Exercise cards */
.exercise-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.exercise-card {
    background-color: var(--black);
    border-radius: 16px;
    padding: 20px 22px;
    color: var(--white);
}

.exercise-card-top {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 10px;
}

.exercise-name {
    font-size: 1.05rem;
    font-weight: 700;
    font-family: var(--font-en);
}

.exercise-badge {
    flex: 0 0 auto;
    font-size: 9px;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding: 4px 10px;
    border-radius: 100px;
    white-space: nowrap;
}

.badge-beginner {
    background-color: #a8d5a2;
    color: #1a3315;
}

.badge-intermediate {
    background-color: #7ab8e8;
    color: #0f2d40;
}

.badge-advanced {
    background-color: #e8c97a;
    color: #3a2c05;
}

.badge-1percent {
    background-color: transparent;
    color: var(--accent);
    border: 1px solid var(--accent);
}

.exercise-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 14px;
    font-size: 11px;
    color: var(--grey-mid);
    margin-bottom: 12px;
}

.exercise-meta span {
    display: inline-flex;
    align-items: center;
}

.exercise-desc {
    font-size: 0.85rem;
    color: rgba(245, 245, 240, 0.85);
    line-height: 1.55;
    margin-bottom: 12px;
}

.exercise-link {
    display: inline-block;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.03em;
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid var(--accent);
    padding-bottom: 1px;
}

.exercise-link:hover {
    opacity: 0.75;
}

.no-link-note {
    font-size: 11px;
    color: var(--grey-mid);
    font-style: italic;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--grey-mid);
    font-size: 0.9rem;
}

/* ==========================================================
   STARTING POINT OVERLAY (index.html)
   ========================================================== */

.level-overlay {
    position: fixed;
    inset: 0;
    background-color: var(--black);
    z-index: 300;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    transition: opacity 0.3s ease;
}

.level-overlay.hidden {
    display: none;
}

.level-card {
    max-width: 420px;
    width: 100%;
    text-align: center;
}

.level-kanji {
    font-family: var(--font-jp);
    font-size: 40px;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 8px;
}

.level-title {
    font-family: var(--font-en);
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 10px;
}

.level-sub {
    font-family: var(--font-en);
    font-size: 0.85rem;
    color: var(--grey-mid);
    margin-bottom: 32px;
    line-height: 1.5;
}

.level-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.level-option {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    text-align: left;
    background-color: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 14px;
    padding: 16px 20px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: var(--font-en);
}

.level-option:hover {
    background-color: rgba(255, 255, 255, 0.08);
    border-color: var(--accent);
}

.level-option-name {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--white);
    letter-spacing: 0.02em;
}

.level-option-desc {
    font-size: 0.78rem;
    color: var(--grey-mid);
    line-height: 1.4;
}

/* ---- CHANGE LEVEL LINK ---- */
.change-level-link {
    background: none;
    border: none;
    color: var(--grey-mid);
    font-size: 11px;
    font-family: var(--font-en);
    text-decoration: underline;
    cursor: pointer;
    margin-top: 12px;
    padding: 4px;
}

.change-level-link:hover {
    color: var(--black);
}