/* ── Onboarding carousel ── */
#ob-container {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    position: relative;
    background: radial-gradient(circle at 10% 10%, rgba(124, 187, 255, 0.18) 0, transparent 38%),
        radial-gradient(circle at 85% 80%, rgba(255, 156, 214, 0.16) 0, transparent 40%),
        linear-gradient(135deg, var(--ob-bg-start) 0%, var(--ob-bg-end) 100%);
    overflow: hidden;
    transition: background 0.6s ease;
}

/* 背景彩色光暈 + 霧氣：3 成色彩、7 成暗色 */
#ob-container::before,
#ob-container::after {
    content: '';
    position: absolute;
    inset: -20%;
    pointer-events: none;
    z-index: 0;
}

/* 柔和彩色光暈（緩慢飄移） */
#ob-container::before {
    background:
        radial-gradient(circle at 15% 25%, rgba(129, 230, 217, 0.20) 0, transparent 40%),
        radial-gradient(circle at 80% 30%, rgba(129, 140, 248, 0.24) 0, transparent 45%),
        radial-gradient(circle at 65% 85%, rgba(248, 180, 127, 0.18) 0, transparent 42%);
    mix-blend-mode: screen;
    opacity: 0.55;
    animation: obGlowDrift 28s ease-in-out infinite alternate;
}

/* 細雨 / 塵霧（極低彩度、慢速移動） */
#ob-container::after {
    background-image:
        radial-gradient(circle at 10% 0%, rgba(255, 255, 255, 0.05) 0, transparent 55%),
        linear-gradient(to bottom, rgba(148, 163, 184, 0.18) 0, transparent 40%),
        linear-gradient(120deg, rgba(15, 23, 42, 0.9) 0, rgba(15, 23, 42, 0.4) 40%, transparent 80%);
    background-size: 140% 160%;
    opacity: 0.35;
    animation: obMistDrift 40s linear infinite;
}

#ob-track {
    display: flex;
    flex: 1;
    position: relative;
    z-index: 1;
    transition: transform 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    will-change: transform;
    touch-action: pan-y;
}

.ob-slide {
    min-width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 30px;
    text-align: center;
    color: #fff;
    box-sizing: border-box;
    position: relative;
    overflow: hidden;
}

.ob-icon {
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ob-icon-svg {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: rgba(148, 163, 184, 0.24);
    display: flex;
    align-items: center;
    justify-content: center;
}

.ob-slide h2 {
    font-size: 1.5em;
    margin: 0 0 10px;
    color: #F9FAFB;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    position: relative;
    padding-bottom: 6px;
}

.ob-slide h2::after {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    bottom: 0;
    width: 56px;
    height: 2px;
    border-radius: 999px;
    background: linear-gradient(90deg, var(--ob-accent), rgba(148, 163, 184, 0.0));
    opacity: 0.95;
}

.ob-slide p {
    font-size: 1em;
    color: rgba(255, 255, 255, 0.8);
    max-width: 300px;
    line-height: 1.7;
}

#ob-dots {
    display: flex;
    justify-content: center;
    gap: 8px;
    padding: 14px 0;
}

.ob-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.35);
    transition: background 0.3s, transform 0.3s;
    cursor: pointer;
}

.ob-dot.ob-active {
    background: #fff;
    transform: scale(1.35);
}

#ob-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 24px 36px;
    position: relative;
    z-index: 1;
}

#ob-skip-btn {
    background: rgba(15, 23, 42, 0.8);
    border: 1px solid var(--ob-accent);
    color: var(--ob-accent);
    padding: 7px 16px;
    border-radius: 18px;
    font-size: 0.9em;
    cursor: pointer;
    transition: background-color 0.45s ease, border-color 0.45s ease, color 0.45s ease;
}

#ob-next-btn {
    background: linear-gradient(135deg, var(--ob-accent), var(--ob-accent-soft));
    border: none;
    color: #fff;
    padding: 9px 24px;
    border-radius: 18px;
    font-size: 0.95em;
    cursor: pointer;
    font-weight: 600;
    box-shadow: 0 0 0 rgba(15, 23, 42, 0);
    transition: background 0.45s ease, box-shadow 0.45s ease;
}

#ob-start-btn {
    background: linear-gradient(135deg, #8b5cf6, #ec4899);
    border: none;
    color: #fff;
    padding: 14px 44px;
    border-radius: 30px;
    font-size: 1.1em;
    cursor: pointer;
    font-weight: 700;
    margin-top: 24px;
    box-shadow: 0 4px 18px rgba(74, 144, 226, 0.55);
}

/* ── 六個不同場景：每頁一種彩色光暈 ── */
.ob-slide:nth-child(1) {
    /* 暖紅路燈下的入口 */
    background:
        radial-gradient(circle at 12% 0%, rgba(248, 113, 113, 0.40) 0, transparent 55%),
        radial-gradient(circle at 100% 100%, rgba(248, 150, 112, 0.24) 0, transparent 60%),
        rgba(15, 23, 42, 0.96);
}

.ob-slide:nth-child(1) .ob-icon-svg {
    background: rgba(248, 113, 113, 0.35);
}

.ob-slide:nth-child(1) .ob-icon-svg svg {
    stroke: #fecaca;
}

.ob-slide:nth-child(2) {
    /* 深橘燈光（與黃色拉開） */
    background:
        radial-gradient(circle at 18% 18%, rgba(234, 88, 12, 0.55) 0, transparent 55%),
        radial-gradient(circle at 90% 85%, rgba(253, 186, 116, 0.32) 0, transparent 58%),
        rgba(15, 23, 42, 0.96);
}

.ob-slide:nth-child(2) .ob-icon-svg {
    background: rgba(234, 88, 12, 0.45);
}

.ob-slide:nth-child(2) .ob-icon-svg svg {
    stroke: #ffedd5;
}

.ob-slide:nth-child(3) {
    /* 淡黃色聚光燈（更輕、更柔） */
    background:
        radial-gradient(circle at 50% -10%, rgba(254, 240, 138, 0.55) 0, transparent 62%),
        radial-gradient(circle at -10% 80%, rgba(250, 224, 120, 0.26) 0, transparent 60%),
        rgba(15, 23, 42, 0.96);
}

.ob-slide:nth-child(3) .ob-icon-svg {
    background: rgba(254, 240, 138, 0.45);
}

.ob-slide:nth-child(3) .ob-icon-svg svg {
    stroke: #fefce8;
}

.ob-slide:nth-child(4) {
    /* 舞台邊緣的綠色反光 */
    background:
        radial-gradient(circle at 0% 40%, rgba(52, 211, 153, 0.40) 0, transparent 55%),
        radial-gradient(circle at 100% 0%, rgba(34, 197, 94, 0.22) 0, transparent 60%),
        rgba(15, 23, 42, 0.96);
}

.ob-slide:nth-child(4) .ob-icon-svg {
    background: rgba(52, 211, 153, 0.35);
}

.ob-slide:nth-child(4) .ob-icon-svg svg {
    stroke: #bbf7d0;
}

.ob-slide:nth-child(5) {
    /* 深藍雨夜的反光水面 */
    background:
        radial-gradient(circle at 20% 100%, rgba(59, 130, 246, 0.42) 0, transparent 55%),
        radial-gradient(circle at 100% 40%, rgba(56, 189, 248, 0.24) 0, transparent 58%),
        rgba(15, 23, 42, 0.96);
}

.ob-slide:nth-child(5) .ob-icon-svg {
    background: rgba(59, 130, 246, 0.35);
}

.ob-slide:nth-child(5) .ob-icon-svg svg {
    stroke: #bfdbfe;
}

.ob-slide:nth-child(6) {
    /* 收尾的紫色散場燈光 */
    background:
        radial-gradient(circle at 15% 90%, rgba(167, 139, 250, 0.42) 0, transparent 55%),
        radial-gradient(circle at 95% 10%, rgba(244, 114, 182, 0.26) 0, transparent 58%),
        rgba(15, 23, 42, 0.96);
}

.ob-slide:nth-child(6) .ob-icon-svg {
    background: rgba(167, 139, 250, 0.40);
}

.ob-slide:nth-child(6) .ob-icon-svg svg {
    stroke: #e9d5ff;
}

@keyframes obGlowDrift {
    0% {
        transform: translate3d(0, 0, 0) scale(1);
    }

    50% {
        transform: translate3d(12px, -18px, 0) scale(1.05);
    }

    100% {
        transform: translate3d(-18px, 22px, 0) scale(1.02);
    }
}

@keyframes obMistDrift {
    0% {
        transform: translate3d(0, -6%, 0);
    }

    50% {
        transform: translate3d(-4%, 3%, 0);
    }

    100% {
        transform: translate3d(6%, 10%, 0);
    }
}