夏日牵牛花海报

创作一张竖版中式美学夏日海报，采用柔和水彩/矿物颜料印刷风格。画布：2:3 纵向比例，温暖的象牙色宣纸背景，右侧留有充足的负空间。构图：左侧三分之二区域由从左下向左上斜向延伸的牵牛花藤蔓填满，配有半透明的绿色心形叶片、纤细的卷须、浅色茎干以及少量未绽放的花蕾；右侧三分之一保持大面积留白，用于竖排文字。包含 5 朵醒目的牵牛花：左上中心 1 朵大型淡粉色花朵，上方中心 1 朵小型浅蓝色花朵，中部 1 朵中型薰衣草紫色花朵，左下中心 1 朵大型天蓝色花朵，以及花藤簇右下角 1 朵小型淡粉紫色花朵。每朵花中心均有发光的白色星形花心和精致的放射状脉络。在右上角文字区域附近添加 1 只微小的淡蓝色蝴蝶。排版：在右侧放置大型竖排中文标题 {argument name="main title" default="夏日安好"}，采用优雅纤细的宋体书法，颜色为柔和的天蓝色。在标题右下方添加较小的竖排文字 {argument name="subtitle" default="清风与花影"}，颜色为柔和的橄榄绿，下方配有一枚小型红色印章和一条极细的竖向分割线。视觉风格：空灵、精致、复古的东亚植物插画，具有柔和的颗粒感，采用蓝色、粉色、薰衣草紫、鼠尾草绿和青色的淡雅色调，带有细腻的墨迹质感，无硬轮廓，无现代元素。限制条件：保持设计宁静简洁，保留右侧大面积的象牙色留白，避免写实风格，避免额外文字，避免边框或水印。

Create a vertical Chinese aesthetic summer poster in a soft watercolor / mineral-pigment print style. Canvas: portrait 2:3 ratio, warm ivory rice-paper background with ample negative space on the right. Composition: the left two-thirds are filled with winding morning glory vines rising diagonally from bottom left to upper left, with translucent green heart-shaped leaves, thin curling tendrils, pale stems, and a few unopened buds; the right third remains mostly blank for vertical typography. Include exactly 5 prominent morning glory blossoms: 1 large pale pink blossom in the upper-left center, 1 small light blue blossom near the upper center, 1 medium lavender-purple blossom in the middle, 1 large sky-blue blossom in the lower-left center, and 1 small pale pink-lavender blossom in the lower-right of the vine cluster. Each blossom has a glowing white star-shaped center and delicate radial vein lines. Add exactly 1 tiny pale blue butterfly near the upper-right text area. Typography: place large vertical Chinese title text on the right reading {argument name="main title" default="夏日安好"}, in elegant thin Song-style calligraphy, colored muted sky blue. To the lower right of the title, add smaller vertical text reading {argument name="subtitle" default="清风与花影"} in muted olive green, with a small red seal stamp beneath it and a very thin vertical divider line below. Visual style: airy, refined, vintage East Asian botanical illustration, soft granulation, faded pastel palette of blue, pink, lavender, sage, and teal, gentle ink texture, no hard outlines, no modern objects. Constraints: keep the design calm and uncluttered, preserve the broad blank ivory space on the right, avoid photorealism, avoid extra text, avoid borders or watermark.